Silent mixed corticotroph and somatotroph macroadenomas presenting with pituitary apoplexy

Silent Corticotroph and Somatotroph Double Pituitary Adenoma: A Case Report and Review of Literature

Clinically silent double pituitary adenomas consisting of corticotroph and somatotroph cells are an exceedingly rare clinical finding. In this report, we present the case of a 28-year-old man with a 1-year history of recurrent headaches. Imaging revealed a 2.1 (anterior-posterior) × 2.2 (transverse) × 1.3 (craniocaudal) cm pituitary adenoma invading into the left cavernous sinus and encasing the left internal carotid artery. Endoscopic transnasal resection was performed without complications. Immunohistochemical staining revealed a double adenoma consisting of distinct sparsely granulated somatotroph and densely granulated corticotroph cells that were positive for growth hormone and adrenocorticotropic hormone, respectively. K _i -67 index labeling revealed a level of 6% within the corticotroph adenoma. No increase in serum growth hormone or adrenocorticotropic hormone was found, indicating a clinically silent double adenoma. While transsphenoidal surgery remains a first-line approach for silent adenomas presenting with mass effects, increased rates of proliferative markers, such as the K _i -67 index, provide useful insight into the clinical course of such tumors. Determining the K _i -67 index of silent pituitary adenomas could be valuable in predicting recurrence after initial surgical resection and identifying tumors that are at an increased risk of needing additional therapeutic interventions or more frequent surveillance imaging.

Multiple Pituitary Apoplexy-Cavernous Sinus Invasion as Major Risk Factor for Recurrent Hemorrhage

OBJECTIVE

Pituitary apoplexy is a rare but potentially life-threatening disorder that occurs in up to 10% of adenomas. Whereas risk factors for the initial hemorrhagic event are well described, there is minor knowledge on clinical symptomatic recurrent pituitary apoplexies.

METHODS

At the Medical University of Vienna, 76 patients were surgically treated for clinical symptomatic pituitary apoplexy between 1990 and 2017. Four patients (5.3%) suffered multiple pituitary apoplexies after initial surgery. In this retrospective study, neuroradiologic images, clinical data, and intraoperative findings were reviewed for potential risk factors of multiple apoplexies in pituitary adenomas.

RESULTS

Patients with multiple apoplexies had significantly higher Knosp grading on preoperative imaging (median grade 4), and more frequently observed cavernous sinus invasion intraoperatively (P = 0.01). Consequently, all cases with multiple pituitary apoplexies remained with residual adenoma postoperatively. In cases of residual tumor within the cavernous sinus, recurrent apoplexy occurred in 23.5% of patients. A tumor recurrence/residual was resected significantly earlier in patients with single apoplexy (median 2.2 years) than in patients with multiple apoplexies (median 5.4 years; P = 0.05). Multiple pituitary apoplexies caused significantly greater rates of ophthalmoplegia (75% vs. 14.1%; P = 0.01) and long-term hormone-replacement therapy was necessary in all cases.

CONCLUSIONS

Cavernous sinus invasion and subtotal resection are high risk factors for multiple apoplexies in pituitary adenomas. Early treatment is recommended for residual tumor in the cavernous sinus to minimize the risk of recurrent apoplexy with subsequent worse clinical outcome.

Silent somatotroph pituitary adenomas: an update

Silent growth hormone adenomas (SGHA) are a rare entity of non-functioning pituitary neuroendocrine tumors. Diagnosis is invariably made post-operatively of a tumor immunopositive for GH (and Pit-1 in selected cases) but without clinical acromegaly. Mainly young females are affected, and tumors are often uncovered by investigation for headaches or oligoamenorrhea. Integration of clinical, pathological and biochemical data is required for proper diagnosis. Beside normal IGF-1 levels, a third of SGHAs displays elevated GH levels and some will eventually progress to acromegaly. Almost two-thirds will be mixed GH-prolactin tumors and sparsely-granulated monohormonal GH tumors seems the more aggressive subtype. Recurrence and need for radiation is higher than other non-functioning tumors so close follow-up is warranted.

Symptomatic cystic degeneration of a clinically silent corticotroph tumor of the pituitary gland

Clinically silent corticotroph tumors of the pituitary gland are those tumors that stain for adrenocorticotropic hormone (ACTH) but do not manifest with clinical or laboratory features of Cushing disease. These tumors have been described as exhibiting more aggressive behavior than other nonfunctional pituitary tumors. We present an unusual case of a clinically silent corticotropic adenoma of the pituitary gland that underwent cystic degeneration following recurrence after transsphenoidal surgery and radiation therapy. The patient underwent left frontotemporal craniotomy with resection of the suprasellar mass and decompression of the left optic nerve. Postoperative magnetic resonance imaging demonstrated no further optic chiasm or nerve compression. Patients with clinically silent ACTH-secreting tumors should be monitored for aggressive tumor behavior and may require closer follow-up than those patients harboring other nonfunctional tumors.

Clinically silent somatotroph adenomas are common

OBJECTIVE

Somatotroph adenomas are typically recognized when they secrete GH excessively and cause acromegaly. Both 'silent' somatotroph adenomas (immunohistochemical evidence of GH excess without biochemical or clinical evidence) and 'clinically silent' somatotroph adenomas (immunohistochemical and biochemical evidence but no clinical evidence) have occasionally been reported. The relative frequency of each presentation is unknown. The goal of this study was, therefore, to determine the frequency of clinically silent somatotroph adenomas, a group that is potentially recognizable in vivo.

DESIGN

We retrospectively identified 100 consecutive patients who had surgically excised and histologically confirmed pituitary adenomas.

METHODS

Each pituitary adenoma was classified immunohistochemically by pituitary cell type. Somatotroph adenomas were further classified as 'classic' (obvious clinical features of acromegaly and elevated serum IGF1), 'subtle' (subtle clinical features of acromegaly and elevated IGF1), 'clinically silent' (no clinical features of acromegaly but elevated IGF1), and 'silent' (no clinical features of acromegaly and normal IGF1).

RESULTS

Of the 100 consecutive pituitary adenomas, 29% were gonadotroph/glycoprotein, 24% somatotroph, 18% null cell, 15% corticotroph, 6% lactotroph, 2% thyrotroph, and 6% not classifiable. Of the 24 patients with somatotroph adenomas, classic accounted for 45.8%, subtle 16.7%, clinically silent 33.3%, and silent 4.2%.

CONCLUSIONS

Clinically silent somatotroph adenomas are more common than previously appreciated, representing one-third of all somatotroph adenomas. IGF1 should be measured in all patients with a sellar mass, because identification of a mass as a somatotroph adenoma expands the therapeutic options and provides a tumor marker to monitor treatment.

Modification of hormonal secretion in clinically silent pituitary adenomas

BACKGROUND

Silent pituitary adenomas are a subtype of adenomas characterized by positive immunoreactivity for one or more hormones classically secreted by normal pituitary cells but without clinical expression, although in some occasions enhanced or changed secretory activity can develop over time. Silent corticotroph adenomas are the classical example of this phenomenon.

PATIENTS AND METHODS

A series of about 500 pituitary adenomas seen over a period of 20 years were screened for modification in hormonal secretion. Biochemical and immunohistochemical data were reviewed.

RESULTS

Two cases were retrieved, one silent somatotroph adenoma and one thyrotroph adenoma, both without specific clinical features or biochemical abnormalities, which presented 20 years after initial surgery with evidence of acromegaly and hyperthyroidism, respectively. While the acromegaly was controlled by a combination of somatostatin analogs and growth hormone (GH) receptor antagonist therapy, neurosurgery was necessary to manage the thyrotroph adenoma. Immunohistochemical examination demonstrated an increase in the number of thyroid stimulating hormone (TSH)-immunoreactive cells compared to the first tissue. Apparently, the mechanisms responsible for the secretory modifications are different, being a change in secretory capacity in the silent somatotroph adenoma and a quantitative change in the silent thyrotroph adenoma.

CONCLUSIONS

These two cases, one somatotroph and one thyrotroph adenoma, are an illustration that clinically silent pituitary adenomas may in rare circumstances evolve over time and become active, as previously demonstrated in silent corticotroph adenomas.

[Making the differential diagnosis between pituitary apoplexy and craniopharyngioma]

Pituitary apoplexy is characterized by an abrupt neurological deteriorating condition associated with rapid expansion of the pituitary gland, caused by ischemic necrosis and hemorrhage. Craniopharyngioma may be difficult to distinguish from pituitary apoplexy. In this study, we discuss a case of pituitary apoplexy in a 19-year-old male patient. In our patient, the tumor was confused with a craniopharyngioma because of the suprasellar extension of the tumor on magnetic resonance (MR) images and the hyperintensity in T1-weighted images, the young age of the patient, and the gradually progressive onset of the symptoms. In conclusion, even without a known history of pituitary adenoma or an abrupt onset of the clinical symptoms, the diagnosis of pituitary apoplexy should be considered in a patient with a suprasellar mass hyperintensity in T1-weighted MR images, which may mimic craniopharyngioma.

Histologic and immunohistochemical characterization of spontaneous pituitary adenomas in fourteen cynomolgus macaques (Macaca fascicularis)

Pituitary adenomas were identified in 14 of 491 (2.9%) cynomolgus macaques evaluated from 1994 to 2004. Cases included male (8) and female (6) cynomolgus macaques ranging from 18 to 32 years of age. Seven of the pituitary adenomas caused gross enlargement of the pituitary gland that was visible on postmortem examination, whereas the remaining 7 were multifocal microadenomas identified on histologic examination. A total of 35 adenomas were identified in the 14 macaques, 6 of which were being treated for diabetes mellitus. Mean (+/- SD) pituitary weight was 0.31 +/- 0.42 g, compared with 0.07 +/- 0.02 g for 430 historical control animals (P < 0.0001). Immunohistochemical staining for follicle-stimulating hormone, luteinizing hormone, prolactin, human growth hormone, thyroid-stimulating hormone, and adrenocorticotropic hormone was applied to pituitary tissue from all cases. Immunostaining revealed 22 of 35 (62.9%) lactotroph adenomas, 5 of 35 (14.3%) plurihormonal cell adenomas, 3 of 35 (8.6%) corticotroph adenomas, 2 of 35 (5.7%) null cell adenomas, 1 of 35 (2.9%) somatotroph adenomas, 1 of 35 (2.9%) mixed corticotroph-somatotroph adenomas, 1 of 35 (2.9%) mixed lactotroph-corticotroph adenomas, 0 of 35 gonadotroph adenomas, and 0 of 35 thyrotroph adenomas. This study represents the first extensive retrospective case series performed to evaluate the histologic and immunohistochemical characteristics of pituitary adenomas in cynomolgus macaques. Our findings indicated that macaque pituitary adenomas frequently had mixed histologic appearance and hormone expression, and that, similar to human pituitary adenomas, prolactin-secreting neoplasms were the most prevalent type.

A spectrum of behaviour in silent corticotroph pituitary adenomas

Silent corticotroph adenomas (SCA) are pituitary tumours positive on immunohistochemical staining for ACTH but without clinical evidence of Cushing's disease in the patient. Previous reports suggest that these tumours may behave in a more aggressive way then other pituitary adenomas. We have followed the natural history of SCA and assessed whether histopathological indices predict tumour behaviour. We identified 22 patients in whom trans-sphenoidal surgery was performed for a non-functioning adenoma (NFA) with positive immunostaining for ACTH between 1990 and 2000 and examined the history of their disease. Patients were followed up for a mean of 4.8 years. A total of 86.7% of patients had documented visual deficits at presentation. In four cases hypercortisolaemia was observed later in the course of the disease. Two patients died as a result of their SCA and 33.3% of tumours recurred. Recurrence was more frequent in patients treated with adjuvant radiotherapy. Pathological indices (increased mitotic range and Ki-67) did not predict recurrence or malignant transformation. We suggest that certain 'silent' corticotroph tumours may have the potential for ACTH secretion leading to hypercortisolaemia at a later stage in the disease. The possibility of transformation to a more aggressive tumour needs to be considered in all SCA.

Co-localization of honeycomb golgi and ACTH granules in a giant ACTH-producing pituitary adenoma

We document the co-localization of honeycomb golgi and ACTH-immunopositive granules in giant ACTH-producing pituitary adenoma cells. A 42-yr-old woman presented with Cushing's disease and a giant adenoma that invaded the sphenoid and cavernous sinus. She underwent transsphenoidal surgery followed by radiation therapy. Some of the adenoma cells were ACTH-positive and upon electron-microscopic (EM) study most were found to contain sparse granules and no type-I filaments. In many cells the golgi complex had undergone partial or total vacuolar transformation that resulted in the appearance of honeycomb golgi. Immunohistochemical study of mirror sections of portions containing cells with honeycomb golgi revealed that the cells with honeycomb golgi showed ACTH-immunopositivity. Honeycomb golgi, which was formerly considered a morphological marker of gonadotroph adenomas in females, has previously been identified in large ACTH-producing pituitary adenomas but there has been no direct evidence that individual cells with honeycomb golgi are cells that produce ACTH. Our immunohistochemical documentation of ACTH-immunoreactivity in individual adenoma cells containing honeycomb golgi clearly confirms that honeycomb golgi is not confined only to gonadotroph adenomas in females. Rather, the existence of honeycomb golgi in cells of other adenoma types may be due to their low hormone production and/or to disturbances in the regulation of the exocytotic pathway.

Management of pituitary apoplexy

Pituitary apoplexy is a rare clinical syndrome caused by sudden haemorrhaging or infarction of the pituitary gland, generally within a pituitary adenoma. Headache of sudden and severe onset is the main symptom, associated with visual disturbances or ocular palsy. Signs of meningeal irritation or altered consciousness may complicate the diagnosis. Corticotropic deficiency (secondary adrenal failure) may be life-threatening if untreated. Computed tomography (CT) or magnetic resonance imaging (MRI) confirm the diagnosis by revealing a pituitary tumour with haemorrhagic and/or necrotic components: CT is most useful in the acute setting (24 - 48 h), MRI is useful for identifying blood components in the subacute setting (4 days to 1 month). Owing to the highly variable course of this syndrome and the limited individual experience, the optimal management of acute pituitary apoplexy is controversial. Some authors advocate early transphenoidal surgical decompression for all patients, whereas others adopt a more conservative approach for selected patients (those without visual acuity or field defects and with normal consciousness). Glucocorticoid treatment must always be initiated immediately, at a dose of hydrocortisone 50 mg every 6 h.

Late recurrent bleeding after surgical treatment for pituitary apoplexy

Pituitary apoplexy is an uncommon syndrome characterised by sudden onset of headache, meningeal signs, visual disturbances, ophthalmoplegia and confusion. Documented recurrent apoplexy or treated apoplexy is even rarer with only few reports in the literature. Between 1994 and 2001, 18 patients were treated for pituitary apoplexy at Bayindir Medical Centre through transsphenoidal route. In all, topical bromocriptine was applied after tumour resection as described by Ozgen. We hereby present the cases of two patients with recurrent apoplexy 3 and 7 years after the initial surgical treatment for pituitary adenoma with apoplexy. The patients were treated non-surgically with success. Additional treatment in the form of radiosurgery was found necessary for the first patient. Surgical excision of the pituitary tumours with apoplexy reduces the risk of recurrent bleedings but eradication is not a rule. These patients need to be followed closely in the postoperative period for possible recurrence of bleeding.

[Silent corticotroph adenomas: presentation of two cases that presented with pituitary apoplexy]

Among the group of pituitary adenomas surgically treated, about 25-30% are not associated with clinical or analytical findings of hormonal hypersecretion. The development of immunohistochemical techniques has allowed the demonstration of a subgroup of adenomas that show immunoreactivity against several hormones among the group of, apparently, non-functioning adenomas. This subgroup has been called silent adenomas. Silent adenomas positive for ACTH show a singular clinical picture and different from those adenomas producing Cushing's disease, as they present more frequently as macroadenomas, with more frequent pituitary apoplexy, invasion of cavernous or sphenoidal sinus and recurrences. We present two new cases of silent corticotroph adenomas in two female patients that presented with pituitary apoplexy, one of them after giving birth after a normal full-term pregnancy. Both of them presented with macroadenomas that invaded the sphenoidal and cavernous sinus. Although both tumors were immunoreactive for ACTH, none of the patients presented clinical or analytical findings compatible with Cushing's disease.

Clinical Characteristics of Silent Corticotrophic Adenomas and Creation of an Internet-accessible Database to Facilitate Their Multi-institutional Study

OBJECTIVE

Silent corticotrophic adenomas (SCAs) of the pituitary gland present as clinically nonfunctioning sellar lesions, with normal serum and urine hormone testing results, but stain positively for adrenocorticotropic hormone in immunohistochemical analyses. These tumors are now more readily recognized, but determination of their natural history and responses to treatment is difficult because of their rarity. We report the diagnoses and outcomes for a series of patients with SCAs, and we describe the creation of an Internet-accessible database (www.hsc.virginia.edu/neuro/neurosurgery/pituitary.html) for collection of multi-institutional data on these lesions.

METHODS

The medical records of patients with documented SCAs who were treated at the University of Virginia between 1991 and 2002 were reviewed. A comprehensive data collection form was then created and posted online.

RESULTS

Twenty-seven patients with SCAs were identified, with a female predominance (70%, P = 0.04). Headache was the most common presenting symptom (70%), followed by visual field deficits (52%), acute or subacute pituitary apoplexy (33%), cavernous sinus syndrome (18.5%), and hypopituitarism (11.1%). Extrasellar extension was noted for 92.6% of patients on preoperative magnetic resonance imaging scans. Transsphenoidal surgery was performed for all patients. Follow-up information was available for all patients (median, 60 mo; range, 3–254 mo). Postoperatively, 33% of patients received radiotherapy. Recurrence was noted for 37% of all patients and 41.7% of patients who did not receive postoperative radiotherapy.

CONCLUSION

SCAs, although clinically nonfunctioning, may behave like aggressive adrenocorticotropic hormone-secreting adenomas and therefore should receive vigorous follow-up monitoring, with consideration being given to the recommendation of radiotherapy in cases with residual tumor.

Full-blown Cushing's disease after an episode of pituitary apoplexy

The present study reports a rare case of full-blown Cushing's disease several years after an episode of pituitary apoplexy. A 60 year-old woman complained of muscular weakness and generalized malaise. Ten years ago she had an episode of pituitary apoplexy. Diabetes mellitus was diagnosed at age 56, and thereafter she had been controlled her plasma glucose with diet therapy and oral hypoglycemic agents. She exhibited cushingoid feature of moon face and central obesity. Both plasma ACTH and serum cortisol levels were elevated to 170 pg/ml and 19.6 microg/dl, respectively. Dexamethasone suppression test showed that a large dose of 8 mg dexamethasone, but not a small dose of 2 mg, suppressed the pituitary-adrenocortical axis. CRH and methyrapone caused increases in plasma ACTH and serum cortisol levels. Brain T(1)-weighted magnetic resonance imaging depicted a low signal of pituitary tumor, which was not enhanced by gadolinium. The pituitary tumor was removed by transsphenoidal adenomectomy, and immunohistochemistry revealed an ACTH-producing adenoma. The evidence suggested the possibility that the two pituitary tumors with dormant period of several years were a recurrence of ACTH-producing tumors in the present patient.