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Profiles
of the Endocrine Clinic:
A Decade of the Massachusetts General Hospital
Neuroendocrine Clinical Center
by: Beverly M. K. Biller, Brooke
Swearingen* Nicholas T. Zervas*, Anne Klibanski
Neuroendocrine Clinical Center, Neuroendocrine
Unit, Department of Medicine , and *Neurosurgical Service, Massachusetts
General Hospital, Boston MA 02114
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Used with
Permission:
A variation of an article published in the
Journal of Clinical Endocrinology and Metabolism
[JCE&M v82:n6:1997 p1668-1674]
Copyright © 1977 by the Endocrine Society
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DEVELOPMENT
OF THE NEUROENDOCRINE CLINICAL CENTER
In 1985 the Massachusetts General
Hospital Neuroendocrine Clinical Center was founded, in order
to provide a multidisciplinary approach to patients with pituitary
and hypothalamic disorders. The Center was developed because of
the recognition that there was fragmentation of care for patients
undergoing medical treatment, surgery or radiation therapy for
pituitary and hypothalamic disorders. Although there were independent
areas of expertise in neurosurgery, neuroendocrinology, radiation
oncology and neurology at the Massachusetts General Hospital,
as well as neuroophthalmologists at the adjacent Massachusetts
Eye and Infirmary, there was no coordinated program of specialty
services to provide an integrated approach to patients. In addition,
it was clear that innovative clinical research programs exploring
the pathogenesis and treatment of pituitary disease would be facilitated
by centralized patient services and a broad referral base. A partnership
was therefore formed with neurologists and neurosurgeons who coordinated
their schedules to provide a weekly unified day for outpatient
consultations and multidisciplinary case reviews. Links were also
established with radiation oncology, for patients needing radiation
therapy for sellar or hypothalamic masses, with neuroophthalmology,
to provide access to detailed evaluation for optic chiasm compression
or involvement of the cranial nerves in the cavernous sinus, and
with neuropathology and neuroradiology to coordinate access to
state-of-the-art diagnostic techniques. A major advantage for
patients, particularly those traveling from other states or countries,
was the coordination of consultations by all these services into
a 24-48 hour period. Experienced neuroendocrine nursing was also
incorporated to provide better patient monitoring and teaching.
The three major objectives of the new Center were 1) excellence
in patient care, 2) establishment of a patient base for innovative
clinical research studies and 3) professional and patient education.
A weekly interdisciplinary Neuroendocrine Case Conference was
established as the cornerstone of coordinated patient care and
physician education. This was to provide a forum for staff neuroendocrinologists,
neurosurgeons, neurologists, and radiation oncologists to reach
a multidisciplinary consensus for a diagnostic and therapeutic
plan for each patient seen that week in the Center. Local primary
care providers, endocrinologists, fellows, residents and medical
students were also invited to participate in these conferences.
An office suite was designed which included patient consultation
rooms, the Pituitary Test Center for performing dynamic hormone
tests on site, and a conference room for formal case review.
Since its founding in 1985, the Neuroendocrine
Clinical Center has grown substantially in patient volume and
personnel to become a major national and international referral
center for patients with pituitary and hypothalamic disorders.
Initially staffed by one endocrinologist, one neurologist and
one neurosurgeon on one afternoon a week, it now is comprised
of 3 weekly teaching sessions with a total of 7 endocrine fellows
as well as rotating medicine and neurology residents and medical
students seeing patients under supervision by 4 staff neuroendocrinologists,
a neurologist and 2 neurosurgeons. There are also several separate
weekly staff sessions. The total volume at the inception of the
Clinical Center was approximately 100 patient visits per year;
it is now well over 1,000 visits annually. The most consistent
reason for growth of the Center is that referring physicians believe
that this type of cohesive multidisciplinary program is needed
for patients with complex pituitary and hypothalamic diseases.
Despite the fact that many patients come from other states or
countries, permission for out-of-plan coverage is often obtained
from insurance carriers, because of the unique strengths of the
Center. Many patients are referred because of the specific expertise
of individual staff endocrinologists in areas such as prolactinomas,
Cushing's disease, and acromegaly. Referrals are also directed
toward the expertise of the neurosurgeons, who are world-renowned
for their abilities at curative transsphenoidal adenomectomy with
minimal morbidity. With well over 1,000 transsphenoidal surgeries
performed at MGH over the past 15 years currently undergoing analysis,
it is clear that the many years of experience are beneficial to
patients. In addition, one of the world's largest experiences
with stereotactic radiosurgery using proton beam therapy for residual/recurrent
pituitary adenoma is now available through the Center. The expertise
of neuropathologists at Massachusetts General Hospital in the
diagnosis and characterization of pituitary adenomas and in pituitary
pathology research also plays a key role in the high level of
patient care.
The second reason for recent growth
of the Center has been that it has served as a major site for
the investigation of pathogenesis and treatment of pituitary disorders.
The findings that 1) the majority of clinically nonfunctioning
tumors are of gonadotroph origin, that 2) pituitary tumors are
monoclonal, that 3) inhibin subunits may play an important role
in tumor phenotype and proliferation and that 4) osteoporosis
is a major clinical consequence of hyperprolactinemic hypogonadism
in men and women have all emerged from investigations in the Center.
The Neuroendocrine Clinical Center was one of the initial sites
pioneering the use of octreotide in acromegaly and has worked
towards developing availability of new dopamine agonists such
as CV205-502 and cabergoline for prolactinomas. The Center has
designed studies addressing whether adults with acquired growth
hormone deficiency should receive long-term replacement of this
hormone. Many physicians refer their patients to the Center in
order to provide them with access to the most innovative diagnostic
or therapeutic approaches. For example, over 100 patients with
Cushing's syndrome have undergone bilateral inferior petrosal
sinus sampling at Massachusetts General Hospital.
A third reason for a recent increase
in patient referrals relates to an expanding base of patient awareness
groups. There are a number of groups which promote awareness in
pituitary disorders, and such groups typically refer patients
to major medical centers where there is the combined expertise
of neuroendocrinology, neurology, neurosurgery and radiation oncology
in order to provide the most comprehensive approach to pituitary
tumors.
PATTERNS OF
PATIENT REFERRALS
At the initiation of the Center,
hyperprolactinemia was the most common referral diagnosis. The
Center began at a time when it was a novel concept that medical
treatment could be primary therapy for nearly all prolactinoma
patients, including those with visual field abnormalities, and
this was one of the pioneering approaches of the Center. However,
as gynecologists and internists have become more familiar with
prolactinomas, such patients have been less frequently referred
to endocrinologists. Many prolactinoma referrals are now more
difficult cases, such as patients who have failed medical management
with bromocriptine or have other complicated issues, such as associated
neuroleptic use or a cystic component to their mass. There has
been a steady increase in the number of patients referred specifically
because of the availability of technologic procedures, such as
patients with Cushing's syndrome referred for CRH-stimulated bilateral
inferior petrosal sinus sampling, and patients referred for specialized
proton beam therapy of pituitary or parasellar central nervous
system lesions such as menigioma, chordoma or chrondrosarcoma.
An increasing number of patients have also been referred because
of access to research protocols which provide newer dopamine agonists,
somatostatin analogue, growth hormone, and growth hormone releasing
peptides. The most recent year in the Neuroendocrine Clinical
Center saw the largest number of referrals being from radiation
oncology (to evaluate radiated patients for hypopituitarism),
followed by neurosurgery, general internal medicine and endocrinology.
One of the most challenging tasks of the Neuroendocrine staff
has been to provide a consultation which meets the specific preference
of the referring physician. The role of the Neuroendocrine Clinical
Center staff in the long-term care of the patient is dependent
on the choices of the referring physician and the patient. Referral
can be for a second opinion, for limited perioperative endocrine
management in patients undergoing transsphenoidal surgery at Massachusetts
General Hospital, for the development of a diagnostic and treatment
plan in conjunction with the primary physician, or for long-term
management by the Center physicians. In the many cases referred
by other endocrinologists, the Neuroendocrine Clinical Center
staff feel strongly that their role should be limited to providing
a second opinion, or to perioperative care in the case of a hospitalized
pituitary tumor patient.
PATIENT POPULATIONS
Patients referred to the Neuroendocrine
Clinical Center have a wide variety of presentations, but many
elements of the neuroendocrine evaluation are similar. History,
physical examination and biochemical testing address whether there
is evidence of anterior pituitary hormone excess or deficiency.
The presence of posterior pituitary dysfunction also provides
useful information, because a patient presenting with DI or SIADH
is likely to have a malignant or infiltrative process rather than
a pituitary adenoma.
A typical day in a Neuorendocrine
Clinical Center session included the following new patients:
A 28 year old dentist from South
America with a classic history of acromegaly, presented with headache
and increased difficulty manipulating his dental instruments over
the past year because of enlarging hands. He was referred to the
Neuroendocrine Clinical Center by a physician in New York, to
undergo curative transsphenoidal surgery at the MGH.
A 20 year old male who had recently
been hospitalized in the neurosurgical ICU for closed head trauma
associated with diabetes insipidus. He underwent an insulin tolerance
test to determine whether the steroids given for brain edema had
suppressed his adrenal axis.
A 57 year old panhypopituitary male
status post craniotomy and radiation therapy for a craniopharyngioma
referred for growth hormone stimulation testing with clonidine,
to determine eligibility for a clinical research study investigating
growth hormone replacement.
A 40 year old woman with Cushing's
syndrome (diagnosed by her neighbor who had read a magazine article)
referred by her internist for evaluation and treatment.
Follow-up patients seen that day
were:
A 32 year old woman from Connecticut
five years status post surgery and cranial irradiation for a chrondrosarcoma,
evaluated on an annual basis for development of hypopituitarism.
Three premenopausal women with microprolactinomas
doing well on dopamine agonist therapy.
A 27 year old female with hyperprolactinemia
induced by neuroleptics and a 3 mm abnormality on head MRI, stable
on follow-up scan.
Two patients several years status
post transsphenoidal surgery for nonfunctioning macroadenomas
doing well with no evidence of recurrence clinically or radiographically.
A 34 year old patient with residual
acromegaly following transsphenoidal surgery and radiation, under
control with subcutaneous octreotide injections.
Hyperprolactinemia:
The most common diagnosis seen in
the Center is pituitary adenoma, accounting for 45% of cases.
Hyperprolactinemia accounts for nearly half of these cases and
includes idiopathic, micro-or macroprolactinomas, and drug-induced.
Several new idiopathic/microprolactinomas are seen each week;
medical treatment with bromocriptine is begun if the patient has
hypogonadism, infertility or clinically significant galactorrhea.
Patients intolerant of bromocriptine are treated with pergolide
or with the investigational agent, cabergoline, on a compassionate
use protocol. Macroprolactinoma patients have historically been
treated with bromocriptine, but currently many such patients are
being offered participation in a new cabergoline trial because
of its high rate of patient acceptance, due to the low incidence
of side effects and only once-a-week dosing. The dose escalation
in prolactinoma patients with visual compromise proceeds much
more rapidly than with other patients, and visual field testing
is repeated at frequent intervals to document the expected rapid
improvement. Surgical intervention is used for prolactinomas when
there is absence of response to medical therapy in a macroadenoma
(often due to a cystic component), an episode of acute hemorrhage/apoplexy,
complete intolerance to all dopamine agonists in some patients
with infertility or hypogonadism, and patients taking neuroleptics
who need control of a mass lesion.
Clinically
Nonfunctioning Pituitary Adenomas:
Approximately 30% of patients with
pituitary tumors seen at the Center have clinically nonfunctioning
adenomas. Patients with these tumors typically present with symptoms
due to mass effect, such as headaches or visual field loss. Others
present with central hypogonadism, hypothyroidism or hypoadrenalism
leading to the finding of a sellar mass. However, it is more common
for these disorders to go undiagnosed until a mass is seen on
brain imaging, with the symptoms of hormone deficiencies present
in retrospect. At least half of patients with nonfunctioning pituitary
adenomas present incidentally, such as when a skull film or CT
scan is done following a head injury or when sinus films are performed
such as in a patient with recurrent sinusitis. Patients with sellar
masses and no clinical evidence of acromegaly, Cushing's disease
or prolactinoma undergo detailed hormone testing confirming that
the lesion is biochemically nonfunctioning. The use of specialized
glycoprotein hormone subunit serum assays such as a-subunit or
FSHb can confirm the pituitary origin of sellar masses. Patients
with clinically nonfunctioning macroadenomas larger than 1 cm
typically undergo transsphenoidal surgery to protect the adjacent
neurologic structures such as the optic chiasm and cranial nerves
III-VI. In many cases, large nonfunctioning macroadenomas can
be completely resected, particularly if there is no lateral extension
into the cavernous sinuses. Substantial recovery of bitemporal
hemianopsia is seen in up to 70% of cases even if there have been
long standing deficits. A typical hospital stay following transsphenoidal
surgery is now 3-4 days with outpatient sodium levels arranged
for the week following discharge to monitor for late SIADH. The
morbidity rate is extremely low, at approximately 1% or less for
serious complications in over 1000 patients with all types of
pituitary tumors (visual worsening 0.4%, meningitis 0.4%, CSF
rhinorrhea requiring repair 1%, and epistaxis requiring embolization
0.002%). The mortality rate for both of the pituitary neurosurgeons
at Massachusetts General Hospital is zero. Patients are routinely
retested for recovery of pituitary function postoperatively as
many patients no longer need hormone replacement after decompression
of the normal pituitary gland. Long term followup of patients
from 1-15 years after transsphenoidal surgery reveals a low rate
of hypopituitarism directly attributable to surgery alone. Only
ten percent of patients who do not receive radiation following
surgery require replacement of at least one hormone more than
a year after surgery and many of these patients were hypopituitary
prior to surgery, due to the compressive effects of the tumor.
In contrast, following a combination of surgery and radiation,
45% of patients require adrenal replacement, and 55% require thyroid
replacement.
Medical therapy is rarely used for
nonfunctioning adenomas because of the lack of effectiveness in
most patients; recurrences are treated with radiation and/or repeated
transsphenoidal surgery. A minority of patients with a-subunit
secreting tumors may show a small degree of mass reduction with
somatostatin analogue therapy. Rarely, patients who are not surgical
candidates because of concurrent medical problems may be treated
with radiation as a primary modality. In such cases, serum hormone
markers confirming a pituitary adenoma is essential for appropriate
radiation dosing and management.
A number of patients are seen for
"incidentalomas" with a sellar lesion of 1 cm or smaller,
and these patients are typically followed, if there is no evidence
of hormone abnormalities, visual field or cavernous sinus involvement.
This includes a detailed evaluation for evidence of subtle hypersecretion
from "silent" tumors including IGF-I, PRL and urine
free cortisol levels. The first follow-up scan is performed at
3-6 months, then annually (and subsequently at increasing intervals
if no change is seen), with transsphenoidal surgery performed
if there is enlargement of the lesion.
Cushing's Syndrome:
Sixteen percent of pituitary tumor patients seen at the Neuroendocrine
Clinical Center have Cushing's disease. Patients with Cushing's
syndrome are most often referred to the Neuroendocrine Clinical
Center by endocrinologists who have already performed an evaluation
and are requesting bilateral inferior petrosal sinus sampling
with CRH to distinguish between pituitary and ectopic Cushing's
or are requesting a second opinion in a complex case. There has
been a significant increase in the number of patient self referrals
as well. Bilateral inferior petrosal sinus catherterization is
performed as an outpatient procedure by the Vascular Radiology
Department, and is arranged in advance so that the patient spends
24-48 hours in Boston with the results typically available in
2 days. Many such patients who are confirmed to have pituitary
Cushing's subsequently undergo transsphenoidal surgery at the
Massachusetts General Hospital because of the high neurosurgical
cure rate. Over the 18 years since 1978, the cure rate for microadenomas,
defined as profound hypoadrenalism postoperatively (urine free
cortisol <30 mcg/24h, serum cortisol <3 mcg/dl), is 84%.
Diagnostic and surgical techniques have improved, and over the
past 4 years, the cure rate for new diagnosed Cushing's microadenomas
is 96% with 48 of 50 patients cured. Forty-six of these were cured
with a single transsphenoidal operation; two patients required
a second operation, usually performed within a few weeks of the
initial procedure. The recurrence rate since 1978 is 6%. No patients
cured over the past 4 years have yet recurred. In those Cushing's
disease patients whose long term postoperative care will be at
the Neuroendocrine Clinical Center, the endocrinologic focus is
on providing as rapid a steroid taper as possible without inducing
steroid withdrawal symptoms. The comprehensive recovery program
for cured Cushing's patients may also include coordination with
physical therapy for patients with severe proximal myopathy and
with psychiatry for patients with affective symptoms. Most patients
are markedly improved clinically within 6 months and fully recovered
by one year, including intact hypothalamic-pituitary-adrenal axis
function.
Acromegaly:
- Acromegaly represents approximately
10% of the pituitary adenomas seen at the Neuroendocrine Clinical
Center. Such patients are most often referred by endocrinologists,
with the goal of providing the patient with the best chance of
curative transsphenoidal surgery. However, many are referred by
other specialists such as the gastroenterologist who realized
that a patient with multiple colon polyps had acromegaly as their
source, the otolaryngologist seeing a patient for hearing loss
who noted overgrowth of palatal soft tissue, or the plastic surgeon
performing a bilateral carpal tunnel release and noting fleshy
palms. In addition to the standard evaluation with IGF-I and/or
oral glucose suppression of GH, the Neuroendocrine Clinical Center
has recently described the use of serum IGFBP3 levels as an additional
diagnostic method in cases where conventional tests yield borderline
results.
- Transsphenoidal adenomectomy remains
the primary therapeutic modality in patients with acromegaly.
Using a normal IGF-I as a definition of cure, 100% of microadenomas
associated with acromegaly (10/10) have been cured over the past
4 years. However, most acromegalics present with macroadenomas.
Over the past 4 years, 45 of 55 acromegalics seen in the Center
have sellar masses = 1 cm. Sixty-nine percent of such patients
were cured with transsphenoidal surgery. Among macroadenoma patients
not cured surgically, over three- quarters had tumor invasion
of the cavernous sinus and/or sphenoid sinus; and were therefore
not considered surgically curable, but were debulked. Those patients
not cured experienced a 45% decline in IGF-I from preoperative
levels. There have been no recurrences among cured acromegalics.
- Patients with acromegaly who are
not cured because of large tumor size and/or extension into the
cavernous sinus have access to radiation therapy, including conventional
fractionated radiation and single dose stereotactic radiosurgery
with proton beam, which minimizes the radiation to adjacent structures.
With the availability of effective medical therapy, the indications
for radiation therapy have become less clear, and this will be
an important issue to address in the future. Because of the morbidity
and increased mortality associated with acromegaly, medical therapy
is administered to all patients with biochemical evidence of residual
tumor following surgery, regardless of whether they have received
radiation. Many patients are first given a limited (3-4 months)
therapeutic trial of bromocriptine, particularly those with minimally
elevated IGF-I levels post-operatively, despite its low rate of
success in normalizing serum IGF-I levels (approximately 8% in
combined series), because it is available orally and costs significantly
less than octreotide. For the majority of those patients with
active acromegaly who do not achieve biochemical control with
bromocriptine, octreotide therapy is initiated. Patients are taught
subcutaneous octreotide self-injection by the Neuroendocrine Clinical
Center nurse, and compliance is excellent. Patients who require
more frequent dosing to achieve IGF-I normalization or headache
control are offered a subcutaneous mini pump for constant drug
delivery. Neuroendocrine Clinical Center patients are offered
access to new investigative agents as they become available; all
acromegalics who initiated treatment with octreotide here will
be contacted when longer acting somatostatin analogues become
available for research use in the United States.
Post-Radiation
Patients:
The second most frequent diagnosis group seen in the Center,
representing 21% of cases, includes patients who have received
radiation therapy to the hypothalamic or pituitary region for
a number of central nervous system tumors including meningiomas,
chordomas, chondrosarcomas, and other parasellar lesions. These
patients are followed prospectively, from the time of radiation,
to monitor for the development of hypopituitarism. The most common
laboratory abnormality in the first several years after radiation
is hyperprolactinemia, which develops in association with destruction
of hypothalamic dopaminergic neurons. Often the first clinical
symptoms are oligomenorrhea in a woman or decreased libido and
impotence in a man, which respond well to bromocriptine therapy
to normalize the prolactin, if the gonadotroph axis remains intact.
While hypopituitarism can occur within months of radiation, most
patients develop no abnormalities for several years. There is
a wide variability in the number of axes affected, with some patients
developing panhypopituitarism and others being normal, or experiencing
only partial pituitary deficiency up to 10 years later. Annual
evaluations in all patients with a history of parasellar radiation
include cortrosyn stimulation testing, free T4 index, menstrual
history in women and testosterone levels in men. Patients are
instructed in the need for lifelong hormone monitoring following
radiation therapy and in the symptoms of hypopituitarism so that
they can seek attention between visits if needed.
Other
Neuroendocrine Disorders:
Miscellaneous neuroendocrine disorders
comprise the remaining patients referred to the Center. Some are
patients who benefit from the participation of a staff neurologist
in the Clinical Center, such as those who have neurologic disorders
associated with endocrine dysfunction. These conditions include
catamenial seizures, catamenial migraine and other headaches,
and parasellar tumors such as tuberculum sella meningiomas, and
craniopharyngiomas. A final subgroup of patients seen in the Neuroendocrine
Clinical Center includes the several patients a year who are referred
with pituitary apoplexy, often in transfer from another hospital
where a hemorrhagic sellar mass has been found on evaluation of
severe headache and/or third cranial nerve palsy. Such patients
are treated as neurosurgical emergencies, with high dose steroids
to reduce edema and preclude acute adrenal crisis, and immediate
transsphenoidal decompression. Most patients experience full neurologic
recovery but become panhypopituitary. Recurrence of the underlying
tumor, which is often necrotic on pathology, is uncommon.
Even in this Clinic comprised of
many patients with rare diseases, there are "zebras."
For example, there are several patients with unusual sellar lesions
such as granular cell tumors, dysgerminomas, and Rathke's pouch
cysts. A number of patients are followed with unusual causes of
hypopituitarism such as neurosarcoid, histiocytosis, Sheehan's
syndrome and bilateral carotid artery aneurysms. Other cases seen
in the Center include lymphocytic hypophysitis in a postmenopausal
woman, a case of biopsy proven intrasellar salivary gland and
an actor who, during a fencing duel scene, sustained a rapier
injury through the nares to his pituitary gland.
Geographic
Scope:
From what geographic area are patients
served? One-third of patients are derived from the Boston urban
area. Thirty to 45% of patients are from elsewhere in Massachusetts
and an additional 10-20% are from other parts of New England.
Twelve to 20% of patients come from the rest of the United States,
and approximately 7% are referred from abroad.
CLINICAL RESEARCH
A major focus of the Neuroendocrine
Clinical Center has always been a partnership of patient care
with clinical research. There has been a long-standing history
of both basic and clinical investigation to explore questions
related to the pathogenesis, diagnosis, and treatment of pituitary
tumors. The first clinical research protocols addressed whether
women seen at the Center with amenorrhea and hyperprolactinemia
were subject to any metabolic consequences of their disorder.
These investigations lead to the extensive area of research that
has linked hyperprolactinemic hypogonadism to osteoporosis, so
that protection of bone mass has become an indication for treatment
of hyperprolactinemic amenorrheic women. Similarly, research regarding
the risk of osteoporosis in hypogonadal men was initiated in the
Center. These investigations have been extended to include other
neuroendocrine causes of osteoporosis, such as hypothalamic amenorrhea
and adult growth hormone deficiency. A second research focus has
been the diagnosis and treatment of pituitary adenomas. The use
of serum markers such as alpha subunit in a nonfunctioning lesions
and more recently the use of IGFBP3 in some cases of acromegaly
have represented diagnostic advances. The Neuroendocrine Clinical
Center has been a major site for the multicenter trials of octreotide
in acromegaly, cabergoline in prolactinomas, and continues to
investigate potential medical therapies for nonfunctioning adenomas.
A third major clinical research initiative has been the diagnosis
and therapy of acquired growth hormone deficiency in the adult.
Studies have been designed to investigate questions including
1) distinguishing acquired GHD from decreased somatotroph function
in normal aging, 2) defining physiologic growth hormone replacement
in adults and determining effects on specific end organs, and
3) the novel use of IGF-I in states of GH resistance. In addition,
studies of new forms of testosterone replacement are underway.
Basic science studies have paralleled some of the in vivo work,
addressing in vitro tumor response to new medical therapies as
well as incorporating innovative studies examining pituitary hormone
regulation and tumor pathogenesis. For example, the question as
to whether Cushing's disease is of hypothalamic or pituitary origin
was addressed in molecular studies which showed that the majority
of corticotroph adenomas are monoclonal and arise from a signal
cell, implying a genetic mutation as the cause. In contrast, hyperplastic
pituitary corticortroph tissue from a patient with an ectopic
CRH-secreting bronchial carcinoid was polyclonal, implying a multicellular
origin derived from diffuse stimulation of the pituitary by the
excess CRH. Extensive cell culture secretion studies, immunocytochemical
staining and molecular investigations lead to the characterization
of the majority of "nonfunctioning" pituitary tumors
as gonadotroph in origin. More recent research has included work
with new pituitary peptides and detailed evaluation of somatostatin
receptors. A partnership with neuropathology has also been important
in exploring potential markers of nonfunctioning tumor recurrence
and the role electron microscopy may play in the clinical management
of patients with pituitary tumors in the future. It has become
increasingly clear, using sophisticated pathologic techniques,
that pituitary tumors represent an extremely heterogeneous group.
This information may become useful as pathologic characteristics
are correlated with clinical features such as likelihood of recurrence
or response to medical therapy. The past decade of research in
the Neuroendocrine Clinical Center has yielded over 60 original
reports and 20 reviews of neuroendocrine subjects.
EDUCATIONAL
INITIATIVES
Table I: Neuroendocrine
Educational Initiatives
Endocrine Fellowship Training
Neuroendocrine Clinical Case Conference
Neuroendocrine Research Conferences
Housestaff Neuroendocrine Elective
Neuroendocrine Speakers Bureau
Visiting Professor/Scientist Preceptorship
Neuroendocrine Clinical Center Newsletter
Physician and Patient Pituitary Symposia
Internet Services
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One of the primary mandates of the
Neuroendocrine Clinical Center has been education. This has been
directed both at physicians and patients as shown in Table 1.
Endocrine Fellowship
Training:
A major component of Neuroendocrine
Clinical Center education is that it serves as an essential aspect
of the Massachusetts General Hospital Endocrine Fellowship Training
Program. Three weekly Neuroendocrine Clinic sessions provide the
fellows a unique opportunity to follow a pituitary tumor patient
from initial evaluation and diagnosis through long term care.
Fellows perform a comprehensive office evaluation under staff
supervision, and during the visit conduct dynamic diagnostic testing
such as cortrosyn stimulation, glucose-suppressed GH or insulin
tolerance testing. Each fellow follows his or her patients longitudinally,
if the Center has primary responsibility for endocrine management,
for at least a year, and can choose to maintain their Neuroendocrine
Clinic patients for all 3 of the fellowship years. The fellows
also have the opportunity to observe their patients' procedures,
such as bilateral inferior petrosal sampling, and transsphenoidal
surgery. When a patient has undergone pituitary adenomectomy,
the fellows manage the perioperative endocrine issues such as
monitoring for diabetes insipidus and/or SIADH, administering
steroids, and testing the hypothalamic-pituitary-adrenal axis
prior to discharge. If the surgery was performed for Cushing's
disease, the fellow evaluates for cure during the hospitalization,
because a second transsphenoidal operation is usually immediately
performed in the few cases not initially cured. Patients are seen
by the same fellow at the 6 week postoperative follow-up visit,
to ascertain whether there has been any damage to (or recovery
of) the hypothalamic-pituitary-gonadal or thyroidal axes, and
to determine whether the tumor has been cured, biochemically and/or
in terms of tumor mass, depending on the tumor type. Pathology
findings, including immunocytochemical staining for all anterior
pituitary hormones, are reviewed. Options for adjunctive therapy
(medical and radiation) are reviewed in detail with patients who
have residual tumors. If the patient will be returning to a referring
physician, the fellow receives instruction about communicating
the perioperative history, pathology results, and long term treatment
recommendations to provide a smooth transition. In addition, the
weekly multidisciplinary Clinical Case Conference provides a venue
for fellows, medical students and residents to participate in
a group discussion of all cases seen that week in the Center including
a review of laboratory test results and MRI scans, thereby expanding
their experience beyond only those cases they have seen themselves.
Neuroendocrine
Conference:
A monthly Neuroendocrine scientific
conference addressing current clinical and research topics in
pituitary and hypothalamic diseases is attended by Massachusetts
General Hospital physicians as well as endocrinologists in the
community. There are two purposes of these conferences. The first
goal is providing the Endocrine Fellows, residents and primary
care providers with a thorough didactic overview of Neuroendocrinology;
this is conducted during the first half of the academic year by
having staff physicians in all the divisions of the Center provide
an annual lecture curriculum covering such topics as the evaluation
of patients with Cushing's syndrome, history and method of transsphenoidal
surgery, hypothalamic disorders, radiation of sellar region tumors,
pituitary pathology, neuroophthalamologic evaluation of patients
with sellar masses, and sellar neuroradiology. The second purpose
of the Center is to provide staff endocrinologists with a forum
for current clinical and basic science research. Some of these
sessions, which occur during the second half of the academic year,
are conducted by members of the Neuroendocrine Clinical Center,
with staff presenting their research work; others are by invited
speakers, with recent topics including "Growth Hormone Releasing
Peptides," "Somatostatin Receptors: Structure and Physiology,"
"Adrenal Insufficiency in H.I.V. -Associated Disease",
"Genetics and Management of Endocrine Neoplasia Syndromes"
and "Clinical Vignettes from the Sella."
Massachusetts
General Hospital House Staff Elective:
The Neuroendocrine Clinical Center
offers a 2 week intensive elective in neuroendocrinology to medical
residents at the Massachusetts General Hospital. The resident
attends the daily general endocrinology visit rounds, then participates
in all of the fellow and staff Neuroendocrine clinics during the
week. Arrangements are made for the resident to attend the transsphenoidal
surgeries being performed during the elective, and he/she then
takes primary responsibility for the inpatient hormonal management.
A syllabus and regular didactic sessions reviewing the principles
of neuroendocrinology are also provided, and teaching cases, which
include photographs of patients, are discussed with the staff
preceptor. Special emphasis is placed on considering pituitary
disorders in the differential diagnosis of patients in the medical
residents' clinics, and on knowing how to evaluate properly for
hypopituitarism. Because these problems are not routinely emphasized
on the inpatient medical wards, participants in this elective
have been very enthusiastic about the unique experience it provides.
Visiting
Physician/Scientist Preceptorship:
A recent addition to the Neuroendocrine
Clinical Center teaching program has been a Visiting Physician/Scientist
Preceptorship Program. Initiated in response to requests by physicians
from abroad, the visiting endocrinologist typically spends time
in the Center observing patient evaluations, hearing case presentations,
attending conferences and transsphenoidal surgery. It has been
an interesting forum for exchanging information about different
approaches to the evaluation and treatment of pituitary tumor
patients.
Speakers
Bureau and Newsletter:
Two activities of the Neuroendocrine
Clinical Center provide education beyond the setting of Massachusetts
General Hospital and Harvard Medical School. The staff of the
Center provides a speakers bureau which has been used both nationally
and internationally, offering a variety of clinical and research
topics in neuroendocrinology. Some are reviews geared at a general
audience such as for Medical Grand Rounds, while others provide
an in-depth discussion of a focused topic appropriate for endocrinologists.
Speakers have also been used in a Visiting Professor capacity,
reviewing complex neuroendocrine cases at other institutions and
discussing possible approaches. Neuroendocrine staff typically
provide more than 30-40 off campus lectures regarding neuroendocrine
topics annually throughout the United States. In addition, staff
members have chaired scientific meetings related to neuroendocrine
topics including The International Pituitary Congress and Pituitary
Symposia at Endocrine Society meetings. The Center publishes an
annual newsletter, mailed to physicians in New England, in which
current neuroendocrine topics of interest are reviewed. Recent
articles have included: "Advances in Recombinant Human Growth
Hormone Replacement Therapy in Adults," "Clinical Uses
of Corticotropin-Releasing Hormone in the Evaluation of Patients
with Cushing's Syndrome," and "Clinically Nonfunctioning
Pituitary Adenomas: Characterization and Diagnosis." The
Neuroendocrine Clinical Center is also on the internet (http://Neurosurgery.mgh.harvard.edu)
at a site which contains the full text of the newsletter. Internet
services include the educational material provided above, and
access to all service facilities and clinical research programs
of the Neuroendocrine Clinical Center.
Beyond these formal teaching activities,
there are also many informal interactions about patient care conducted
by the Neuroendocrine Clinical Center. The Neuroendocrine staff
typically receives 10-25 calls each week from physicians requesting
to "run a case by." These phone requests can range from
less than one minute, such as asking where to find a particular
assay, or to ask how to refer a patient to Boston for bilateral
inferior petrosal sinus sampling, to more than half an hour reviewing
detailed lab results and requesting suggestions for the next step
in a specific patient's care. The majority of such queries are
from endocrinologists but calls from general internists and gynecologists
have been increasing rapidly over the past few years as physicians
are under pressure to avoid subspecialty referrals.
Finally, the educational role of
the Neuroendocrine Clinic has recently extended to patients, with
preparation of educational pamphlets such as a "A Patient's
Guide to Acromegaly" and editing an NIH patient brochure
entitled "Cushing's Syndrome." The Center has also served
as a base for patient support groups which conduct meetings at
Massachusetts General Hospital. Recently, a Pituitary Awareness
Day was held at the Massachusetts General Hospital for patients
and their families in conjunction with the Pituitary Tumor Network
Association. Similar events have also been conducted at several
other major pituitary centers in the United States. Patient education
is a key aspect of the role of the Neuroendocrine nurse who conducts
a weekly clinic, providing direct patient teaching, such as in
the use of intramuscular testosterone or subcutaneous octreotide
injections.
In summary, ten years of the Neuroendocrine
Clinical Center at the Massachusetts General Hospital has seen
it grow into an international referral center for the evaluation
and treatment of both pituitary tumors and disorders of the hypothalamic-pituitary
region. It has served as a major facility for clinical research
as well as basic science investigations regarding the pathogenesis
and treatment of pituitary tumors. The key feature of this Center
is its multidisciplinary composition, with close involvement of
pituitary endocrinologists, experienced pituitary neurosurgeons,
neurologists, radiation oncologists and endocrine nursing as well
as availability of neuroophthalmologists, in order to provide
an integrated approach to patient care which includes access to
innovative clinical research programs.
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