Corticotroph pituitary carcinoma: case report and literature review

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 2, specific diseases

Pituitary adenomas are rare in children and young people under the age of 19 (hereafter referred to as CYP) but they pose some different diagnostic and management challenges in this age group than in adults. These rare neoplasms can disrupt maturational, visual, intellectual and developmental processes and, in CYP, they tend to have more occult presentation, aggressive behaviour and are more likely to have a genetic basis than in adults. Through standardized AGREE II methodology, literature review and Delphi consensus, a multidisciplinary expert group developed 74 pragmatic management recommendations aimed at optimizing care for CYP in the first-ever comprehensive consensus guideline to cover the care of CYP with pituitary adenoma. Part 2 of this consensus guideline details 57 recommendations for paediatric patients with prolactinomas, Cushing disease, growth hormone excess causing gigantism and acromegaly, clinically non-functioning adenomas, and the rare TSHomas. Compared with adult patients with pituitary adenomas, we highlight that, in the CYP group, there is a greater proportion of functioning tumours, including macroprolactinomas, greater likelihood of underlying genetic disease, more corticotrophinomas in boys aged under 10 years than in girls and difficulty of peri-pubertal diagnosis of growth hormone excess. Collaboration with pituitary specialists caring for adult patients, as part of commissioned and centralized multidisciplinary teams, is key for optimizing management, transition and lifelong care and facilitates the collection of health-related quality of survival outcomes of novel medical, surgical and radiotherapeutic treatments, which are currently largely missing.

Crooke Cell Adenoma Confers Poorer Endocrinological Outcomes Compared with Corticotroph Adenoma: Results of a Multicenter, International Analysis

BACKGROUND

Crooke cell adenomas (CCAs) are a rare, aggressive subset of secretory pituitary corticotroph adenomas (sCTAs) found in 5%-10% of patients with Cushing disease. Multiple studies support worse outcomes in CCAs but are limited by small sample size and single-institution databases. We compared outcomes in CCA and sCTA using a multicenter, international retrospective database of high-volume skull base centers.

METHODS

Patients surgically treated for pituitary adenoma from January 2017 through December 2020 were included.

RESULTS

Among 2826 patients from 12 international centers, 20 patients with CCA and 480 patients with sCTA were identified. No difference in baseline demographics, tumor characteristics, or postoperative complications was seen. Microsurgical approaches (60% CCA vs. 62.3% sCTA) were most common. Gross total resection was higher in CCA patients (100% vs. 83%, P = 0.05). Among patients with gross total resection according to intraoperative findings, fewer CCA patients had postoperative hormone normalization of pituitary function (50% vs. 77.8%, P < 0.01) and remission of hypersecretion by 3-6 months (75% vs. 84.3%, P < 0.01). This was the case despite CCA having better local control rates (100% vs. 96%, P < 0.01) and fewer patients with remnant on magnetic resonance imaging (0% vs. 7.2%, P < 0.01). A systematic literature review of 35 studies reporting on various treatment strategies reiterated the high rate of residual tumor, persistent hypercortisolism, and tumor-related mortality in CCA patients.

CONCLUSIONS

This modern, multicenter series of patients with CCA reflects their poor prognosis and reduced postsurgical hormonal normalization. Further work is necessary to better understand the pathophysiology of CCA to devise more targeted treatment approaches.

An update on, and genetics of refractory adenomas of childhood

Pituitary adenomas in childhood tend to be more frequently due to germline genetic changes and are often diagnosed at late stages due to delayed recognition by pediatricians and other caretakers who are not familiar with this rare disease in childhood. As a result, often, pediatric pituitary adenomas are aggressive or remain refractory to treatment. In this review, we discuss germline genetic defects that account for the most common pediatric pituitary adenomas that are refractory to treatment. We also discuss some somatic genetic events, such as chromosomal copy number changes that characterize some of the most aggressive pituitary adenomas in childhood that end up being refractory to treatment.

Corticotroph pituitary carcinoma with skeletal metastases masquerading as ectopic ACTH syndrome: a long and winding road to diagnosis

Summary

Pituitary carcinoma is a rare type of malignancy and only accounts for 0.1-0.2% of all pituitary tumours. Most pituitary carcinomas are hormonally active and they are mostly represented by corticotroph and lactotroph carcinomas. Corticotroph carcinoma can present as symptomatic Cushing's disease or can evolve from silent corticotroph adenoma which is not associated with clinical or biochemical evidence of hypercortisolism. We hereby present a case of a bone-metastasized corticotroph pituitary carcinoma masquerading as an ectopic adrenocorticotropic hormone (ACTH) syndrome in a patient with a history of a non-functioning pituitary macro-adenoma. Our patient underwent two transsphenoidal resections of the primary pituitary tumour followed by external beam radiation therapy. Under hydrocortisone substitution therapy she developed ACTH-dependent hypercortisolism without arguments for recurrence on pituitary MRI and without central-to-peripheral ACTH-gradient on inferior petrosal sinus sampling, both suggesting ectopic production. Ultimately, she was diagnosed with an ACTH-secreting vertebral metastasis originating from the primary pituitary tumour. This case report demonstrates the complex pathophysiology of pituitary carcinoma and the long diagnostic work-up. Certain features in pituitary adenoma should raise the suspicion of malignancy.

Learning points

The diagnosis of pituitary carcinoma can only be made based on documented metastasis, therefore, due to the often long latency period between the detection of the primary tumour and the occurrence of metastasis, the diagnostic work-up most often spans over multiple years. Pituitary carcinoma including corticotroph carcinoma is very rare in contrast to pituitary adenoma and only accounts for 0.1-0.2% of all pituitary tumours. Histopathology in pituitary adenoma should certainly accomplish the following goals: accurate tumour subtyping and assessment of tumoural proliferative potential. Repeated recurrence of pituitary adenoma after surgical resection, a discrepancy between biochemical and radiological findings, resistance to medical and radiation therapy, and silent tumours becoming functional are all hallmarks of pituitary carcinoma. Silent corticotroph adenomas are non-functioning pituitary adenomas that arise from T-PIT lineage adenohypophyseal cells and that can express adrenocorticotropic hormone on immunohistochemistry, but are not associated with biochemical or clinical evidence of hypercortisolism. Silent corticotroph adenomas exhibit a more aggressive clinical behaviour than other non-functioning adenomas. Treatment options for corticotroph carcinoma include primary tumour resection, radiation therapy, medical therapy, and chemotherapy. Sometimes bilateral adrenalectomy is necessary to achieve sufficient control of the cortisol excess.

Prevalence and clinical characteristics of Crooke's cell adenomas in 101 patients with T-PIT-positive pituitary adenomas: Case series and literature review

PURPOSE

We aimed to perform a retrospective analysis of a rare subtype of corticotroph adenoma, Crooke's cell adenoma, to better understand its clinical features.

METHODS

We collected T-PIT-positive pituitary adenomas and screened Crooke's cell adenomas from January 2020 to December 2021 in our center. Case reports of such tumors were also collected through a literature search. Clinical data such as biochemical tests, imaging examinations, and pathological data of the above cases were analyzed.

RESULTS

A total of 101 T-PIT-positive patients were treated in our center in the last 2 years, and 4 were finally pathologically diagnosed with Crooke's cell adenomas. All of these patients were male with elevated adrenocorticotropic hormone levels, and 50.0% presented with hypercortisolemia, Cushing's syndrome, visual impairment, and headache. The tumor diameter was significantly larger in these 4 patients (37.0 mm) than in the other patients (26.0 mm), and their tumor invasive behavior was more pronounced. Cases reported in the literature were mainly female (72.8%), and the clinical presentation was also dominated by Cushing's syndrome (65.1%) and hormonal dysfunction. Tumors were more common as macroadenomas (33.2 mm) and suprasellar growths (63.8%). The tumor recurrence rate was as high as 55.6%, with 6 cases progressing to pituitary carcinomas and 7.7% of tumor-related deaths. Our further integrated analysis of our center and reported cases revealed that gender, Cushing's syndrome, visual dysfunction, hormonal disorders, and tumor growth characteristics were statistically different in different tumor categories.

CONCLUSION

Crooke's cell adenoma is a tumor subtype with obvious clinical aggressive behavior, and an in-depth analysis of its clinical characteristics may assist in developing a comprehensive treatment plan.

Tumor invasion to the spinal region after primary surgery: A case report

Background

It is believed that pituitary carcinoma is a rare disorder and arise from the transformation of benign invasive macroadenomas, and the process of this transformation takes place slowly.

Case Presentation

A 51-year-old man presented with the clinical features of Cushing syndrome and walking impairment who was diagnosed with metastatic corticotroph pituitary carcinoma to the spine region, 6 years after the initial resection of a primary invasive pituitary adenoma. He made a visit to neurosurgery and endocrinology clinic with the chief complaint of weight gain, facial and extremities swelling, paresthesia, weakness, motion and speaking impairments, and HTN which all appeared through the last 1 year; hormonal laboratory tests showed urine free cortisol (UFC) 197.8 and 367. 30 ug/24hrs (36-137), cortisol 8 am after 1 mg overnight dexamethasone test 375 ng/mL (50-250) and ACTH 59 pg/mL. MRI study revealed a mass in the brainstem with the compression effect on spinal region, pituitary imagine does not differ from the last MRI. He underwent a neurosurgery for spinal mass resection, which was successful and the total mass was resected. After surgery, the patient's condition became better.

Conclusion

Pituitary carcinoma is a rare entity impossible to recognize as a primary tumor because its diagnosis by definition requires the presence of metastasis. Clinical awareness of the rare possibility for aggressive adenomas will progress, to metastasize is essential to appropriately monitor patients for possible early detection and treatment of pituitary carcinoma.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

Aggressive pituitary tumors in the young and elderly

Aggressive pituitary tumors (APTs) represent rare pituitary adenomas (PAs) with local invasion of surrounding tissues, increased risk for multiple recurrence, rapid tumor growth, or resistance to standard therapies. The most common APTs in children and adolescents are giant prolactinomas and somatotropinomas. Few cases of Crooke's cell adenomas, silent corticotroph adenomas and pituitary carcinomas have also been reported in the literature. Pediatric patients with APTs have higher risk of harboring germline genetic defects, most commonly in the MEN1 and AIP genes. Since certain genetic defects confer a more aggressive behavior to PAs, genetic testing should be considered in tumors with young onset and positive family history. The management of pediatric APTs involves usually a combination of standard therapies (surgical, medical, radiation). Newer agents, such as temozolomide, have been used in few cases of pediatric pituitary tumors with promising results. In the elderly, PAs are more commonly non-functioning. Their management often poses dilemmas given the coexistence of age-related comorbidities. However, standard surgical treatment and temozolomide seem to be safe and well tolerated in elderly patients.

Gamma Knife Radiosurgery in Patients with Crooke Cell Adenoma

BACKGROUND

Crooke cell adenoma is a very rare subtype of pituitary neoplasm that is known to be clinically aggressive. These tumors can secrete adrenocorticotropic hormone or may be endocrinologically silent. We evaluated the effect of Gamma Knife radiosurgery (GKRS) on endocrine remission and tumor control.

MATERIALS AND METHODS

This study comprised 5 patients (2 men, 3 women; median age at GKRS, 55 years [range, 21-65 years]) with pathology-confirmed Crooke cell adenoma treated with GKRS at the Gamma Knife Center of the University of Virginia. The median time interval between transsphenoidal resection and GKRS was 5.8 months. The median margin dose was 25 Gy (range, 18-25 Gy). Median treated adenoma volume was 3.12 mL. Median follow-up was 107 months (range, 44-122 months).

RESULTS

Tumor control was achieved in all patients. Three patients achieved endocrine remission at the last follow-up. The median time interval to cortisol normalization when off of anti-hormone secreting medication was 12 months (range, 6-24 months). Newly developed or worsening endocrinopathy occurred in 3 patients at 6, 15, and 18 months, respectively. Cranial nerve III neuropathy developed in 1 patient. Two patients required bilateral adrenalectomy at 44 months and 50 months, respectively, following GKRS.

CONCLUSIONS

GKRS appears to be a safe and reasonably effective treatment option for Crooke cell adenoma. Multicenter studies with larger numbers of patients are needed to verify these findings.

Clinically Silent Adrenocorticotropic Hormone-Positive Crooke Cell Adenoma: Case Report and Review of Literature

BACKGROUND

Pituitary adenomas are one of the most common tumors of adulthood; however, subtypes such as Crooke cell adenoma are relatively rare.

CASE DESCRIPTION

We present the case of a 55-year-old woman who presented with new-onset intermittent headache and dizziness. Clinical and laboratory investigations were not suggestive of corticotroph tumor. However, subsequent computed tomography and magnetic resonance imaging scans revealed the presence of a suprasellar pituitary adenoma displacing the optic chiasma superiorly, with hemorrhage and sellar expansion. The lesion was removed by transsphenoidal surgery and the biopsy confirmed the lesion to be a nonfunctioning pituitary macroadenoma. Further investigation revealed that the specimen demonstrated Crooke hyaline changes, with strong immunoreactivity for adrenocorticotropic hormone. However, initial workup and postoperative testing lacked evidence of Cushing disease. There was no sign of recurrence after 1-year follow-up.

CONCLUSIONS

Clinically silent Crooke cell adenomas are rare occurrences, and as such we report this case with investigation of past cases.

Malignant transformation in non-functioning pituitary adenomas (pituitary carcinoma)

Non-functioning pituitary carcinomas (NFPC) are defined as tumours of adenophyseal origin with craniospinal or systemic dissemination, with the absence of a hormonal hypersecretion syndrome. These are a histologically heterogenous group of tumours, comprising gonadotroph, null cell, "silent" tumours of corticotroph, somatotroph or lactotroph cell lineages as well as plurihormonal Pit-1 tumours. NFPC are exceedingly rare, and hence few cases have been described. This review has identified 38 patients with NFPC reported in the literature. Recurrent invasive non-functioning pituitary adenomas (NFPA) were observed in a majority of patients. Various factors have been identified as markers of the potential for aggressive behaviour, including rapid tumour growth, growth after radiotherapy, gain or shift of hormone secretion and raised proliferative markers. Typically, there is a latency of several years from the original presentation with an NFPA to identification of metastases and only 5 cases reported with rapidly progressive malignant disease within 1 month of presentation. Therapeutic options include debulking surgery, radiation therapy and chemotherapy with temozolomide recommended as first line systemic treatment. Although long-term survivors are described, prognosis remains generally very poor (median survival 8 months). Improvements in molecular tumour profiling may assist in predicting tumour behaviour, guide therapeutic choices and identify novel therapies.

Case report: ACTH-secreting pituitary carcinoma metastatic to the liver in a patient with a history of atypical pituitary adenoma and Cushing's disease

Background

Pituitary carcinoma is a rare entity requiring the presence of metastasis to confirm its malignant potential. We report a case of pituitary carcinoma and discuss the diagnosis and management of this lesion in relation to the existing literature.

Case presentation

The patient is a 51-year-old woman with Cushing’s disease and intact adrenal glands who was diagnosed with metastatic pituitary carcinoma to the liver, 29 months after initial resection of an ACTH-secreting primary atypical pituitary adenoma (APA). Prior to detection of this metastasis the patient underwent repeat resection and radiotherapy for residual cavernous sinus disease. The metastatic lesion was detected by interval surveillance of serum ACTH and 24-hour urine cortisol, which despite stable pituitary MRI, were significantly elevated. These abnormalities prompted a PET scan that demonstrated hypermetabolic liver parenchyma, which was suspicious for metastasis on abdominal MRI. An ultrasound-guided liver biopsy demonstrated nests of moderately-differentiated cells with intermediate-sized, monotonous nuclei, distinct nucleoli, and abundant basophilic cytoplasm, confirmed by immunohistochemistry to represent metastatic pituitary carcinoma. The liver lesion was subsequently successfully removed by wedge resection. One year later, the patient’s residual cavernous sinus disease grew markedly, and she was placed on dual-agent chemotherapy consisting of oral temozolomide and capecitabine, with stabilization of her intracranial disease to present, although liver metastases recurred.

Conclusions

Pituitary carcinoma is a rare entity impossible to recognize as a primary tumor because its diagnosis by definition requires the presence of metastasis. Maintaining awareness of the entity and its precursor lesion APA is essential for its accurate pathologic diagnosis and appropriate management.

Silent Crooke's cell corticotroph adenoma of the pituitary gland presenting as delayed puberty

Summary

Corticotroph adenomas are extremely rare in children and adolescents. We present a 15-year-old boy who was investigated for delayed puberty (A1P2G1, bilateral testicular volumes of 3 mL each). There was no clinical or laboratory evidence suggestive of chronic illness, and the initial clinical impression was constitutional delay in puberty. Subsequently, MRI scan of the brain revealed the presence of a mixed cystic and solid pituitary lesion slightly displacing the optic chiasma. The lesion was removed by transphenoidal surgery and the biopsy confirmed the lesion to be pituitary adenoma. Furthermore, the adenoma cells also had Crooke’s hyaline changes and were intensely positive for ACTH. However there was no clinical/biochemical evidence of ACTH excess. There was a spontaneous pubertal progression twelve months after the surgery (A2P4G4, with bilateral testicular volume of 8 mL). Crooke’s cell adenoma is an extremely rare and aggressive variant of corticotroph adenoma that can uncommonly present as a silent corticotroph adenoma in adults. We report for the first time Crooke’s cell adenoma in an adolescent boy presenting with delayed puberty.

Learning points:

Crooke's cell tumors of the pituitary

Crooke's cell adenomas are a rare type of pituitary neoplasm. They produce adrenocorticotropic hormone causing Cushing's disease or may be endocrinologically silent. These tumors are usually invasive, may exhibit aggressive clinical behavior, and often recur with a low success of cure after reoperation and/or radiotherapy. Due to their rarity, they present great difficulties in assessing prognosis, treatment, and clinical management. Neurosurgeons and physicians dealing with pituitary adenomas diagnosed as Crooke's cell adenomas have to be aware of their potential clinical aggressiveness to plan strict follow-up of patients and eventual multimodality treatment. We review here the published cases of Crooke's cell tumors, as well as the clinical and histopathological characteristics of these unusual neoplasms.

Current status on histological classification in Cushing's disease

INTRODUCTION

Managing Cushing's disease remains a challenge. Surgery is the first option of treatment and it offers a high success rate. Even in cases where biochemical remission is not achieved, it is crucial to obtain surgical tissue for morphological diagnosis because the therapeutic approach can be modified according to the findings.

MATERIALS AND METHODS

A literature search was performed using PubMed for information regarding pathology and Cushing's disease.

RESULTS

The histopathological features found in the pituitary gland of patients with Cushing's disease are presented.

CONCLUSION

Different subtypes of ACTH-producing pituitary tumors are recognized and characterized. The significance of finding a normal pituitary gland with or without Crooke's changes is also discussed.

Temozolomide responsiveness in aggressive corticotroph tumours: a case report and review of the literature

Pituitary carcinoma occurs in ~0.2% of resected pituitary tumours and carries a poor prognosis (mean survival <4 years), with standard chemotherapy regimens showing limited efficacy. Recent evidence suggests that temozolomide (TMZ), an orally-active alkylating agent used principally in the management of glioblastoma, may also be effective in controlling aggressive/invasive pituitary adenomas/carcinomas. A low level of expression of the DNA-repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) predicts TMZ responsiveness in glioblastomas, and a similar correlation has been observed in the majority of aggressive pituitary adenomas/carcinomas reported to date. Here, we report a case of a silent pituitary corticotroph adenoma, which subsequently re-presented with Cushing's syndrome due to functioning hepatic metastases. The tumour exhibited low immunohistochemical MGMT expression in both primary (pituitary) and secondary (hepatic) lesions. Initial TMZ therapy (200 mg/m² for 5 days every 28 days-seven cycles) resulted in marked clinical, biochemical [>50% fall in adrenocorticotrophic hormone (ACTH)] and radiological [partial RECIST (response evaluation criteria in solid tumors) response] improvements. The patient then underwent bilateral adrenalectomy. However, despite reintroduction of TMZ therapy (further eight cycles) ACTH levels plateaued and no further radiological regression was observed. We review the existing literature reporting TMZ efficacy in pituitary corticotroph tumours, and highlight the pointers/lessons for treating aggressive pituitary neoplasia that can be drawn from experience of susceptibility and evolving resistance to TMZ therapy in glioblastoma. Possible strategies for mitigating resistance developing during TMZ treatment of pituitary adenomas/carcinomas are also considered.

Management Strategies for Aggressive Cushing's Syndrome: From Macroadenomas to Ectopics

Cushing's syndrome (CS) is a rare but severe clinical condition represented by an excessive endogenous cortisol secretion and hence excess circulating free cortisol, characterized by loss of the normal feedback regulation and circadian rhythm of the hypothalamic-pituitary axis due to inappropriate secretion of ACTH from a pituitary tumor (Cushing's disease, CD) or an ectopic source (ectopic ACTH secretion, EAS). The remaining causes (20%) are ACTH independent. As soon as the diagnosis is established, the therapeutic goal is the removal of the tumor. Whenever surgery is not curative, management of patients with CS requires a major effort to control hypercortisolemia and associated symptoms. A multidisciplinary approach that includes endocrinologists, neurosurgeons, oncologists, and radiotherapists should be adopted. This paper will focus on traditional and novel medical therapy for aggressive ACTH-dependent CS. Several drugs are able to reduce cortisol levels. Their mechanism of action involves blocking adrenal steroidogenesis (ketoconazole, metyrapone, aminoglutethimide, mitotane, etomidate) or inhibiting the peripheral action of cortisol through blocking its receptors (mifepristone “RU-486”). Other drugs include centrally acting agents (dopamine agonists, somatostatin receptor agonists, retinoic acid, peroxisome proliferator-activated receptor γ “PPAR-γ” ligands) and novel chemotherapeutic agents (temozolomide and tyrosine kinase inhibitors) which have a significant activity against aggressive pituitary or ectopic tumors.

Cushing's disease

Cushing’s disease, or pituitary ACTH dependent Cushing’s syndrome, is a rare disease responsible for increased morbidity and mortality. Signs and symptoms of hypercortisolism are usually non specific: obesity, signs of protein wasting, increased blood pressure, variable levels of hirsutism. Diagnosis is frequently difficult, and requires a strict algorithm. First-line treatment is based on transsphenoidal surgery, which cures 80% of ACTH-secreting microadenomas. The rate of remission is lower in macroadenomas. Other therapeutic modalities including anticortisolic drugs, radiation techniques or bilateral adrenalectomy will thus be necessary to avoid long-term risks (metabolic syndrome, osteoporosis, cardiovascular disease) of hypercortisolism. This review summarizes potential pathophysiological mechanisms, diagnostic approaches, and therapies.

Atypical, invasive, recurring Crooke cell adenoma of the pituitary

We report the case of a 49-year-old woman presenting with Cushing disease and visual disturbance. An atypical, aggressive, invasive pituitary tumor regrew despite several surgeries. Detailed morphologic investigation by histology, immunohistochemistry and electron microscopy documented a Crooke cell adenoma, a rare form of ACTH-producing pituitary tumor. Recognition of such adenomas is of importance given their aggressive behavior and tendency to recur. More studies are needed to explain the pathobiology of this not invariably functional pituitary adenoma.

A case of corticotroph carcinoma that caused multiple cranial nerve palsies, destructive petrosal bone invasion, and liver metastasis

A 52-year-old woman experienced sudden onset of double vision due to a right abducens nerve palsy and was diagnosed as having a pituitary macroadenoma that invaded into the right cavernous sinus. Otherwise, she was asymptomatic despite marked elevation of ACTH (293 pg/ml) and cortisol (24.6 μg/dl) levels. The patient underwent transsphenoidal surgery followed by γ-knife radiosurgery (GKR), which healed the diplopia and ameliorated the hypercortisolemia. The excised tumor was diffusely stained for ACTH with a high (15%) Ki-67 labeling index. Early tumor recurrence occurred twice thereafter, producing right lower cranial nerve palsies with petrosal bone destruction at 8 months and an ipsilateral oculomotor nerve palsy at 12 months after GKR; all palsies resolved completely with the second and third GKRs. Hypercortisolemia worsened rapidly soon after the third GKR, and the patient developed marked weight gain, hypokalemia, and hypertension. Multiple liver lesions were incidentally detected with computer tomography and identified as metastatic pituitary tumor on immunohistochemistry. An ACTH-producing adenoma should be followed carefully for early recurrence and/or metastatic spread when the tumor is an invasive macroadenoma with a high proliferation marker level. The unique aggressive behavior and high potential for malignant transformation of this case are discussed.

Malignant pituitary corticotroph adenomas: report of two cases and a comprehensive review of the literature

Corticotroph pituitary carcinomas are tumors, defined by the presence of distant metastases that determine their poor prognosis. The diagnosis and therapy of malignant corticotroph adenomas remains a clinical challenge. The molecular mechanisms of malignant transformation of pituitary adenomas are unclear, although they are believed to arise in an adenoma-to-carcinoma sequence. We describe two cases of malignant Cushing's disease with metastases in liver and bone, respectively. The primary pituitary tumors were treated by a combination of radiotherapy and transsphenoidal surgery, but recurred several times in both patients. The time interval between the diagnosis of Cushing's disease and the discovery of metastases was 32 and 17 years, respectively. In the first case the patient died within 6 months after diagnosis of metastasis, whereas the second patient is alive at a follow-up of 2 years after the discovery of the metastasis. Furthermore, we reviewed all available cases of corticotroph pituitary carcinomas reported in the literature and analyzed their clinical features and therapeutical management. In conclusion, frequent relapses of Cushing's disease, aggressive growth of macroadenoma, Nelson's syndrome after adrenalectomy or persistently high ACTH levels should prompt the clinician to consider the possibility of pituitary corticotroph carcinomas.

Transformation of a pituitary macroadenoma into to a corticotropin-secreting carcinoma over 16 years

OBJECTIVE

To describe a case of a pituitary macroadenoma that differentiated into a corticotropin (ACTH)-secreting carcinoma with metastasis to the thigh.

METHODS

We present a case report with a 16-year follow-up that includes anatomic and endocrine documentation of the history of an ACTH-secreting carcinoma.

RESULTS

A 32-year-old woman presented for evaluation in 1989 because of visual field defects. Magnetic resonance imaging revealed a locally invasive 3-cm macroadenoma. She had no clinical signs of cortisol excess. The patient underwent surgical debulking followed by a course of radiation directed to the pituitary. Results from retrospective immunohistochemical staining with antibodies against ACTH, prolactin, and MIB-1 were negative. Postoperatively, she could not be weaned from exogenous steroids without developing symptoms of adrenal insufficiency. In 1995, she developed left facial palsy and diplopia caused by tumor growth. In 1997, the patient developed progressive symptoms of cortisol excess, which continued after exogenous steroid replacement was discontinued. The patient's clinical status continued to deteriorate because of local mass effect from tumor growth and uncontrolled hypercortisolism. She underwent bilateral adrenalectomy in 2003. The patient remained debilitated in a long-term care facility for 2 years when she was found to have a mass on her left hip. Biopsy results of the obturator muscle revealed metastatic tumor of neuroendocrine origin with strong reactivity to ACTH antibodies and MIB-1 labeling in 8% of tumor cell nuclei.

CONCLUSION

A pituitary tumor can transform into an ACTH-secreting carcinoma in an indolent manner. Patients with invasive pituitary adenomas require long-term surveillance to monitor for differentiation into pituitary carcinoma.

Pituitary carcinoma: diagnosis and treatment

Pituitary carcinomas are rare pituitary tumors that by definition have cerebrospinal and/or systemic metastases. Most of the tumors occur in the setting of multiple recurrences of invasive pituitary adenomas. This article reviews the clinical presentation of these tumors, their neuroimaging and pathological features, tumor pathogenesis, and possible treatment modalities.

Pituitary carcinoma: a review of the literature

Pituitary carcinomas, defined as distant metastases of a pituitary neoplasm, are rare; fewer than 140 reports exist in the English literature. The initial presenting pituitary tumor is usually a secreting, invasive macroadenoma, with adrenocorticotropic hormone (ACTH)--and prolactin (PRL)--secreting tumors being the most common. The latency period between the diagnosis of a pituitary tumor and the diagnosis of a pituitary carcinoma is 9.5 years for ACTH-producing lesions and 4.7 years for PRL-secreting tumors. Survival after documentation of metastatic disease is poor; 66% of patients die within 1 year. Treatment options include additional surgery, radiotherapy, and chemotherapy, all of which are associated with poor results. Future studies will focus on identifying those invasive pituitary tumors most likely to metastasize and treating them aggressively before they progress to pituitary carcinomas.

Molecular defects in the pathogenesis of pituitary tumours

The majority of pituitary adenomas are trophically stable and change relatively little in size over many years. A comparatively small proportion behave more aggressively and come to clinical attention through inappropriate hormone secretion or adverse effects on surrounding structures. True malignant behaviour with metastatic spread is very atypical. Pituitary adenomas that come to surgery are predominantly monoclonal in origin and roughly half are aneuploid, indicating either ongoing genetic instability or transition through a period of genetic instability at some time during their development. Few are associated with the classical mechanisms of tumour formation but it is generally believed that the majority harbour quantitative if not qualitative differences in molecular composition compared to the normal pituitary. Despite their prevalence and the ready availability of biopsy material, at the present time, the precise molecular pathogenesis of the majority of pituitary adenomas remains unclear. This review summarizes current thinking.

Silent corticotroph carcinoma of the adenohypophysis: a report of five cases

We report five silent corticotroph carcinomas of the pituitary gland. They represent 0.05% of adenohypophyseal tumors surgically treated at Mayo Clinic during a 20-year period and about 5% of all reported pituitary carcinomas. The patients (three females and two males), ranging in age from 26 to 58 years (mean 39 years, median 35 years) presented with symptoms of mass effect; none had Cushing's disease. All tumors were initially invasive macroadenomas, recurred locally, and metastasized, three outside the central nervous system. The follow-up period ranged from 2 to 23 years (mean 10.6 years). All patients died, four of disseminated tumor and one of myocardial infarction. Histologically, three of the primary lesions were indistinguishable from an ordinary benign adenoma. Two were initially diagnosed as atypical adenomas as they featured nuclear pleomorphism, prominent nucleoli, mitotic activity, high MIB-1 labeling indices, and p53 overexpression. For the purpose of comparison, 17 silent corticotroph adenomas were also investigated. In addition, the clinicopathologic features of the silent carcinomas were compared with those of a meta-analysis of published Cushing's disease-associated pituitary carcinomas. The silent adrenocorticotropin carcinomas showed a propensity for extraneural dissemination and an outcome similar to those of the Cushing's disease-associated carcinomas. The two patients with initial atypical tumors died with metastases outside the central nervous system at 2 and 4 years, whereas the three patients with tumors lacking atypia died 16, 18, and 23 years after initial sellar surgery.