Clinical and genetic changes in a case of a Cushing's carcinoma

Possible role of a radiation-induced p53 mutation in a Nelson's syndrome patient with a fatal outcome

Nelson's syndrome (NS) is characterized by the appearance and/or progression of ACTH-secreting pituitary macroadenomas in patients who had previously undergone bilateral adrenalectomy for the treatment of Cushing's disease. Such corticotroph macroadenomas respond poorly to currently available therapeutic options which include surgery, radiotherapy and chemotherapy. P53 protein accumulation may be detected by immunohistochemistry in pituitary corticotroph adenomas and it has been suggested that it might be causally related to tumor development. Wild type P53 protein plays an important role in the cellular response to ionizing radiation and other DNA damaging agents and is mutated in many human tumors. In this study we report an adult male patient with NS who underwent both transsphenoidal and transcranial pituitary surgeries, conventional and stereotaxic radiotherapy and brachytherapy. Despite of the efforts to control tumor mass and growth, this macroadenoma displayed relentless growth and aggressive behavior. DNA extracted from the first two surgical samples, as well as DNA from peripheral blood leukocytes disclosed normal p53 sequence. DNA extracted from tumor samples obtained at surgeries performed after pituitary irradiation carried a somatic heterozygous mutation, consisting of a deletion of four cytosines between nucleotides 12,144-12,149 in exon 4 of the p53 gene. This frameshift mutation creates a stop codon in exon 4 excluding the expression of a functional protein from the defective allele. These data demonstrate a possible association between the P53 protein loss of function induced by radiotherapy and the aggressive course of the disease in this patient.

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.

[Molecular aspects of pituitary tumorigenesis]

Pituitary tumors, almost invariably adenomas, are of frequent occurrence, accounting for 10% to 15% of all the intracranial neoplasm. They are classified as microadenomas (< 10 mm) or macroadenomas (> 10 mm) and as secreting or clinically non-secreting (or not functioning) adenomas. These tumors are autonomously capable to release pituitary hormones such as the growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), thyroid stimulating hormone (TSH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The occurrence of metastases, characterizing a pituitary carcinoma, is exceedingly rare. However tumors with aggressive behavior, leading to local invasion, are relatively common. Although the pathogenesis of pituitary tumors is fully characterized, many molecular mechanisms of pituitary tumorigenesis had already been revealed. This review intends to describe advances in the understanding of the involved advances that have been made in the last decade concerning pituitary tumors progression, including the participation of oncogenes, tumor suppressor genes and growth factors.

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: 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.

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.

Distinct clonal composition of primary and metastatic adrencorticotrophic hormone-producing pituitary carcinoma

The pathogenetic mechanisms underlying pituitary tumorigenesis are largely unknown. Previous reports have suggested that aggressive pituitary adenomas and/or carcinomas may be associated with genetic alterations that are distinct from those responsible for the more common and less aggressive pituitary adenomas. Here, we describe the clonal composition of a pituitary carcinoma, its recurrence and its metastasis. The samples studied were from a 48-year-old woman who presented with recurrent Cushing's syndrome. During the 8-year course of her disease, she had an ACTH-producing pituitary carcinoma requiring two transsphenoidal procedures and resection of a metastatic cervical lymph node. Her disease remained active despite surgical resection, external beam irradiation and medical treatment with ketoconazole. Ultimately, bilateral adrenalectomy was performed to control the hypercortisolism. Morphological and immunohistochemical studies revealed that the primary and recurrent pituitary tumours and the metastatic lesion were an endocrine tumour with ACTH and growth hormone immunoreactivity. Primary, recurrent and metastatic tumour DNAs were analysed for X-chromosome inactivation and loss of heterozygosity (LOH) at several microsatellite loci on chromosomes 9,10, 11, 13 and 22. All three lesions were monoclonal in composition as suggested by the pattern of X chromosome inactivation of the PGK-1 allele. Moreover, the primary, recurrent and metastatic lesions demonstrated LOH at the microsatellite allelic markers PYGM and D10S217. In contrast, however, the metastatic lesion showed a loss-to-retention pattern at two distinct loci (IFNA and D22S156) compared to the primary and recurrent pituitary tumours. These findings, while consistent with a clonal composition of the primary and metastatic pituitary lesions, show each clone to be distinct. This is the first description of a metastatic pituitary carcinoma with a distinct clonal composition from its primary source.

Corticotroph pituitary carcinoma: case report and literature review

Pituitary carcinomas, currently defined as primary adenohypophyseal neoplasms with evidence of either brain invasion or metastatic spread, are exceptionally rare. A case of corticotroph pituitary carcinoma is reported. A 17-year-old female first presented with an invasive and clinically non-functioning pituitary macroadenoma. The primary pituitary lesion lacked atypical histological features and retrospective immunohistochemical studies confirmed its corticotrophic nature. Repeated episodes of local recurrence followed together with the acquisition of severe Cushing's disease. Local disease control was not obtained despite repeated surgical decompression and courses of radiation therapy. Systemic dissemination with multiple bone metastases became manifest eleven years after the first presentation. Atypical histological features and Crooke's hyaline change were evident in both the recurrent and metastatic disease. She remains alive at last follow-up with severe complications relating to persisting sellar and metastatic disease and ongoing endocrine dysfunction. A further 32 cases of pituitary corticotroph carcinoma reported in English are reviewed to highlight the clinicopathological features of this rare form of pituitary neoplasm. Difficulties associated with the diagnosis and management of pituitary carcinoma are also discussed.

An ACTH-producing pituitary carcinoma developing Cushing's disease

An autopsy case of an ACTH-producing pituitary carcinoma in a 59-year-old man who developed Cushing's disease is reported. The surgically removed pituitary tumor was diagnosed as chromophobe adenoma, however, pulmonary metastases appeared 2 years after the operation. Autopsy revealed a residual pituitary tumor in the sella turcica with systemic metastases to the lungs, liver, pulmonary lymph nodes, hypothalamus, dura mater, and the subarachnoid space of the midbrain and spinal cord. Immunohistochemistry revealed ACTH positivity in the tumor cells. Further immunohistochemical study showed positive high expression of Ki-67 in the tumor removed at surgery as well as in the autopsied tumor. Ki-67 labeling index provided valuable information about the invasive and proliferative potential compared to noninvasive benign pituitary adenoma.

Multiple endocrine neoplasias in a dog: corticotrophic tumour, bilateral adrenocortical tumours, and pheochromocytoma

In a 10-year-old ovariohysterectomized standard Schnauzer, the finding of dexamethasone-resistant hypersecretion of cortisol, the results of computed tomography, and elevated plasma concentrations of ACTH suggested the presence of both adrenocortical tumour and pituitary-dependent hyperadrenocorticism. The dog made an uneventful recovery after bilateral adrenalectomy and remained in good health for 31/2 years with substitution for the induced hypoadrenocorticism. Then the enlarged pituitary caused neurological signs and eventually euthanasia was performed. The surgically excised right adrenal contained a well-circumscribed tumour of differentiated adrenocortical tissue and in the left adrenal there were two adrenocortical tumours and a pheochromocytoma. The unaffected parts of the adrenal cortices were well developed and without regressive transformation. At necropsy there were no metastatic lesions. The cells of the pituitary tumour were immunopositive for ACTH and had characteristics of malignancy. The present combination of corticotrophic tumour, adrenocortical tumours, and pheochromocytoma may be called 'multiple endocrine neoplasia' (MEN), but does not correspond to the inherited combinations of diseases known in humans as the MEN-1 and the MEN-2 syndromes. It is suggested that the co-existence of hyperadrenocorticism and pheochromocytoma may be related to the vascular supply of the adrenals. Some chromaffin cells of the adrenal medulla are directly exposed to cortical venous blood, and intra-adrenal cortisol is known to stimulate catecholamine synthesis and may promote adrenal medullary hyperplasia or neoplasia.

Adrenocorticotropin-Producing Pituitary Carcinoma with Expression of c-erbB-2 and High PCNA Index: A Comparative Study with Pituitary Adenomas and Normal Pituitary Tissues

Pituitary carcinomas are very rare neoplasms with a poor prognosis. We report a case of Cushing's disease resulting from a pituitary carcinoma in a 22-yr old female, who died of massive hepatic failure. At autopsy, there was invasion of the parasellar structures and vasculature by the tumor, which stained positively only for ACTH. There were two metastatic nodules in the liver, which also stained positively for ACTH. When compared to other cases of Cushing's disease (n = 52), other pituitary adenomas (n = 292). and normal pituitary tissues (n = 21), the pituitary carcinoma was the only one with c-erbB-2 membrane staining in both the sellar-located tissue and liver metastasis. C-erbB-2 staining was present in the cytoplasm of a variable number of cells in 40% of the invasive adenomas (n = 103), while only 1.2% of the noninvasive tumors (n = 241) expressed this protein (p < 0.001). No particular immunohistological type preferentially expressed this protein. In normal pituitary tissues, 10% of the cells expressed cytoplasmic c-erbB-2. A higher index of proliferating cell nuclear antigen (PCNA) in the primary tumor and liver metastasis (10%) was also found compared to other ACTH-secreting adenomas (invasive, 3.4 -t 1 S% vs 1 ii +/- 1.5% in noninvasive) and other pituitary tumors (invasive, 2.9 +/- 1.5% vs 1.5 +/- 1.3% in noninvasive). The PCNA index was significantly higher in invasive tumors than in noninvasive adenomas (p = 0.004). PCNA staining was negative in normal pituitary tissues. Staining for p53, pRB and p(2ras) was negative in the carcinoma and liver metastasis. We suggest that the c-erbB-2 membrane pattern and a higher PCNA index may indicate a worse prognosis in adenohypophyseal neoplasia.