Glucocorticoid- and Androgen-Secreting Black Adrenocortical Adenomas: Unique Cause of Corticotropin-Independent Cushing Syndrome

ObjectiveTo describe the unique association of corticotropin-independent Cushing syndrome caused by cortisoland androgen-secreting black adrenal cortical adenomas with myelolipomatous change.MethodsWe report the clinical, laboratory, radiologic, and pathologic findings from 2 patients who presented with androgen excess and typical signs and symptoms of Cushing syndrome.ResultsEndocrine investigations showed high serum cortisol concentrations that lacked diurnal rhythm, undetectable plasma corticotropin concentrations, and absence of serum cortisol suppression after overnight dexamethasone suppression tests. Serum levels of adrenal androgens were elevated. Computed tomography of the abdomen revealed unilateral adrenal masses (largest lesional diameters 4.0 and 3.1 cm). On the basis of the plurihormonal hypersecretion and the imaging characteristics, adrenocortical carcinoma was considered as a possible diagnosis. However, histopathologic analysis in both patients revealed black adrenal cortical adenomas with myelolipomatous change. After surgery, adrenal androgens normalized, and the signs and symptoms of Cushing syndrome and androgen excess resolved. There was no evidence of recurrent disease at last follow-up.ConclusionsA unique form of corticotropin-independent Cushing syndrome is described: cortisoland androgen-secreting black adrenal cortical adenomas with myelolipomatous change. Although most patients with corticotropin-independent Cushing syndrome associated with androgen excess prove to have adrenocortical carcinoma, the clinician should be aware of the possibility of benign, black adrenal adenomas in this clinical setting. (Endocr Pract. 2011;17:e73-e78)     

Multiple Unilateral adrenal Adenomas in a Patient with Primary Hyperaldosteronism

ObjectiveTo report a rare case of multiple unilateral adrenal adenomas in which immunohistochemistry results confirmed primary hyperaldosteronism in each of 3 adenomas.MethodsWe present the clinical, laboratory, radiographic, and pathologic findings of a case of multiple unilateral adrenal adenomas.ResultsAlthough multiple nodules in both adrenal glands are fairly common in patients with bilateral hyperplasia, multiple unilateral nodules are extremely rare. A 45-year-old woman with a long-standing history of severe hypertension was found to have biochemical parameters consistent with primary hyperaldosteronism, multiple unilateral adrenal adenomas, and immunohistochemical test results confirming primary hyperaldosteronism arising from each of 3 adrenal nodules (measuring 2.2 × 2.2 cm, 1.7 × 0.7 cm, and 0.5 × 0.5 cm).ConclusionThis case illustrates the rare presentation of primary hyperaldosteronism as multiple unilateral adrenal adenomas in which immunohistochemistry results can confirm the suspected preoperative diagnosis as suggested by biochemical and radiographic evidence. (Endocr Pract. 2008;14:76-79)     

Medullary Thyroid Carcinoma Manifesting as an Ovarian Mass: Case Report and Review of Literature

ObjectiveTo report the uncommon case of a woman with abdominal pain and a complex adnexal mass, who was subsequently found to have medullary thyroid carcinoma (MTC) metastatic to the ovary.MethodsWe present the clinical history, physical findings, laboratory and imaging studies, and pathologic findings in a woman with metastatic MTC and locally aggressive disease. The genetic associations, variable clinical course, and histopathologic findings in MTC are reviewed.ResultsA 38-year-old woman with abdominal and pelvic pain underwent a computed tomographic scan of the abdomen, which showed a complex left adnexal mass. After laparoscopic left oophorectomy, histopathologic analysis of the resected ovary suggested the presence of a metastatic neuroendocrine tumor. The patient recovered but was referred to the surgery clinic 3 months later because of hoarseness, a left neck mass, and left-sided vocal cord paralysis. Further work-up was suggestive of MTC, which prompted RET testing for multiple endocrine neoplasia. The patient underwent left thyroid lobectomy and selective lymph node dissection but later required tracheostomy because of tumoral invasion of the trachea, laser debulking of the tumor, and external beam radiation therapy. One year postoperatively, development of a metastatic lesion in her right ovary necessitated a second oophorectomy.ConclusionMTC usually manifests as a solitary thyroid nodule but should be considered in patients with metastatic lesions characterized by neuroendocrine features. This unusual case highlights the biologic and clinical variability of this often aggressive thyroid cancer, which necessitates an attentive work-up, a rigorous operative strategy, and a periodic postoperative surveillance program. (Endocr Pract. 2008;14:351-357)     

An Unusual Variant of Cushing Syndrome

ObjectiveTo discuss the initial clinical manifestations of primary pigmented nodular adrenocortical disease.MethodsWe present a case report of a 4-year-old boy who had the classic clinical features of Cushing syndrome. Results of hormonal investigations are reviewed, and histopathologic findings are illustrated.ResultsInvestigations revealed adrenocorticotropic hormone (corticotropin)-independent Cushing syndrome. Findings on magnetic resonance imaging of the pituitary gland and abdomen were within normal limits. The patient underwent bilateral adrenalectomy. The histopathologic features were consistent with primary pigmented nodular adrenocortical disease.ConclusionPrimary pigmented nodular adrenocortical disease should be suspected in patients with corticotropin- independent Cushing syndrome who have normal findings on adrenal imaging. (Endocr Pract. 2008;14:717-720)     

Adrenal Incidentalomas: Diagnostic Evaluation and Long-Term Follow-Up

ObjectiveTo evaluate the cause and the clinical and laboratory features of adrenal incidentalomas (AI) in 52 patients and to assess the evolution of nonsurgically treated lesions during long-term follow-up.MethodsWe retrospectively analyzed the medical records of 52 patients with AI undergoing routine followup in 2 Brazilian endocrine centers.ResultsIn our study group, nonfunctioning adenomas were the most frequent cause of AI (42%), followed by cortisol-secreting adenomas (15%), metastatic disease (10%), pheochromocytomas (8%), myelolipomas (6%), cysts (6%), carcinomas (4%), lymphomas (4%), tuberculosis (4%), and aldosteronoma (2%). Only 13 lesions (25%) were functioning (8 cortisol-secreting adenomas, 4 pheochromocytomas, and 1 aldosteronoma). Carcinomas were the largest adrenal masses (mean diameter, 11.7 ± 1.3 cm). With the exception of 1 pheochromocytoma, 1 cyst, and 1 myelolipoma, all AI larger than 6 cm were carcinomas. During follow-up of 21 patients with nonsurgically treated AI for 6 to 36 months (mean, 24.8 ± 8.9), no patient had tumor reduction or disappearance. After 12 months of follow-up, however, a 45-year-old woman had adrenal mass enlargement from 3.2 cm to 4.4 cm; the excised lesion proved to be an adenoma. Moreover, evidence of cortisol hypersecretion developed after 24 months of follow-up in a 30-year-old man with a 3.5-cm adenoma in the left adrenal gland.ConclusionOur findings demonstrate that most AI are nonfunctioning benign lesions and emphasize the need for long-term follow-up of patients with conservatively managed lesions, in light of the potential for evolution to hormonal hypersecretion or tumor growth. (Endocr Pract. 2008;14:269-278)     

Bronchogenic Cyst Masquerading As an Adrenal Tumor: A Case of Mistaken Identity

ObjectiveTo describe a patient with a bronchogenic cyst that was erroneously diagnosed as an adrenal tumor and the surgical management strategy to address the operative challenges.MethodsWe summarize the clinical presentation, diagnostic workup, surgical management, and pathologic features of the study patient and review the pertinent literature.ResultsIn this report, we present the case of a 23-year-old woman who underwent retroperitoneoscopic exploration after imaging identified an enlarging left adrenal lesion. Preoperative biochemical testing confirmed that the mass was nonfunctional. No lesion was found after a thorough retroperitoneoscopic exploration under standard high insufflation pressure. Serendipitously, low-pressure inspection for hemostasis after failed exploration enabled discovery of an intradiaphragmatic mass that proved to be a bronchogenic cyst rather than an adrenal tumor. Not only was this a difficult operative dilemma, but it was also an unusual presentation for this tumor.ConclusionsDiscovery of a retroperitoneal or intradiaphragmatic bronchogenic cyst is a rare occurrence. The unusual location and tumor characteristics contributed to near surgical failure. The fortuitous surgical strategy of lowpressure inspection allowed visualization of the tumor for definitive resection. (Endocr Pract. 2012;18:e102-e105)     

Unexpected Clinical Course During Treatment of a TSH-Secreting Pituitary Adenoma

ObjectiveTo report the rare occurrence of a patient with thyrotropinoma that transitioned into a secretory thyro-somatotroph adenoma during medical treatment with somatostatin analogue.MethodsWe report the case of a patient with a thyrotroph pituitary adenoma who developed de novo evidence of growth hormone cosecretion following one year of successful medical treatment.ResultsA 78-year-old woman was diagnosed with a thyroid stimulating hormone (TSH) secreting pituitary macroadenoma (TSHoma) based on classical clinical and biochemical features. There was no clinical or biochemical evidence of growth hormone (GH) cosecretion. She declined surgical resection and was treated with primary medical therapy, octreotide long acting repeatable (LAR), to which she had an antitumor and antisecretory response; however, following 12 months of successful medical treatment she developed de novo hypersecretion of growth hormone despite involution of the tumor mass. TSH-secreting pituitary adenomas may rarely become plurihormonal during apparently successful medical treatment. This may represent an unusual form of secondary resistance to somatostatin analogue or the rarer phenomenon of tumor transformation into a secretory thyro-somatotroph adenoma.ConclusionThe unexpected clinical course of this case highlights the need for careful long-term surveillance in patients with TSH secreting pituitary adenomas. (Endocr. Pract. 2013;19:e88-e91)     

Asymptomatic Bilateral Giant Adrenal Myelolipomas: Case Report and Review of Literature

ObjectiveTo describe an unusual case of bilateral giant adrenal masses caused by a primary adrenal myelolipoma.MethodsWe present the clinical, laboratory, and pathologic findings in a 32-year-old man with bilateral adrenal masses. The previous reports of bilateral myelolipomas also were reviewed.ResultsDuring a routine examination, a 32-year-old Thai man was found to have an asymptomatic abdominal mass. A computed tomographic scan of the abdomen disclosed bilateral adrenal masses; the one on the left was approximately 27 by 24 by 12 cm, and the one on the right side was 9 by 5 by 5 cm. The computed tomographic scan characteristics showed that both masses consisted mainly of low-density tissues (-30 to -90 Hounsfield units), suggestive of fatty component. An endocrinologic evaluation revealed no evidence of adrenal cortical or medullary functional abnormalities. Bilateral adrenalectomy was performed because of the large size of the lesions and the inability to rule out malignant involvement.ConclusionMyelolipoma is a relatively rare benign tumor of the adrenal glands composed of adipose cells and mature hematopoietic elements. Most such lesions are small, asymptomatic, and unilateral; giant or bilateral myelolipomas are quite rare. To our knowledge, our current case may represent the largest bilateral lesions in the literature. (Endocr Pract. 2007;13:667-671)     

Parathyroid Carcinoma in Multiple Endocrine Neoplasia Type 1 with a Classic Germline Mutation

ObjectiveTo report the case of a patient with multiple endocrine neoplasia type 1 (MEN 1) syndrome with concomitant parathyroid carcinoma and a classic MEN1 germline mutation.MethodsWe present the clinical findings, laboratory results, imaging studies, and surgical histopathologic features in a woman with MEN 1 syndrome and concomitant parathyroid carcinoma. We also review the literature regarding patients with similar clinical entities and the use of adjuvant radiotherapy for parathyroid carcinoma.ResultsA 53-year-old woman presented with nausea and severe primary hyperparathyroidism. Computed tomography revealed parathyroid masses, shown later to be bilateral parathyroid carcinomas and adenomas. Magnetic resonance imaging demonstrated a pituitary macroadenoma, and gastrinomas were confirmed by computed tomography and a secretin stimulation test. She was successfully treated with total thyroidectomy, subtotal parathyroidectomy, and adjuvant radiotherapy. Genetic analysis revealed a classic MEN1 germline mutation.ConclusionThis report describes a patient with parathyroid carcinoma occurring in conjunction with MEN 1, further characterizing this rare condition. In contrast to previously described patients, our patient is the first with a classic MEN1 germline mutation, confirming that parathyroid cancer can occur in association with classic MEN 1 genetics. (Endocr Pract. 2009;15:567-572)     

Retroperitoneal Cystic Teratoma Masquerading as an Incidentally Discovered Adrenal Mass

ObjectiveTo report a case of a retroperitoneal cystic teratoma that obscured and compressed the adrenal gland, mimicking a primary adrenal tumor.MethodsThe presenting manifestations, radiographic characteristics, gross and microscopic pathologic features, and results of surgical therapy and long-term follow-up are described.ResultsA 50-year-old African American woman with a 2-year history of low back pain and night sweats had a computed tomographic scan of the abdomen, which revealed an incidental 8 by 4 by 3.5-cm left adrenal mass without a clear plane between the mass and the left crus of the diaphragm. Laboratory studies excluded a functioning adrenal tumor. The tumor was resected laparoscopically. It was compressing but not involving the adrenal gland, nor was it involving the diaphragm. Microscopic evaluation revealed a benign mature cystic teratoma characterized by cystic spaces lined by respiratory epithelium with cartilage, bone, lymphoid tissue, smooth muscle, and ganglionic tissue in the cyst wall. The patient had an uneventful postoperative course and is free of recurrence after 18 months of follow-up.ConclusionAlthough rare, a mature cystic teratoma of the retroperitoneum that compresses the normal adrenal gland may masquerade as a primary adrenal tumor and should be included in the differential diagnosis of a nonfunctioning adrenal incidentaloma. (Endocr Pract. 2011; 17:e130-e134)     

Sustained Remission with the Kinase Inhibitor Sorafenib in Stage IV Metastatic Adrenocortical Carcinoma

ObjectiveTo report our experience using kinase in- hibition therapy with sorafenib in a patient with advanced adrenocortical carcinoma.MethodsWe describe the clinical,laboratory, and ra- diologic findings of the study patient and discuss the clini- cal course with sorafenib therapy.ResultsA 56-year-old woman presented with rapid development of virilization, cushingoid features, hyper- tension, weight gain, and abdominal distension. An 8-cm left adrenal lesion was found on computed tomography, re- moved surgically, and confirmed as adrenal carcinoma on pathologic examination. Postoperative scanning revealed metastases to both lungs and the liver that were confirmed by fine-needle biopsy, thus establishing stage IV disease. Treatment with the adrenolytic agent mitotane failed to halt disease progression. A trial of sorafenib resulted in regres- sion and eventual resolution of bilateral metastatic lung lesions, reduction in size of the hepatic lesion, normaliza- tion of androgen hypersecretion, and marked clinical im- provement. The radiologic and biochemical remission on sorafenib has continued for 28 months.ConclusionMultiple kinase inhibitors such as sorafenib provide targeted oncologic treatment and may be effective in treating advanced adrenal cancer. (Endocr Pract. 2010;16:441-445)     

Plasma Cell Granuloma of The Thyroid: Report of Case and Review of Literature

ObjectiveTo report the 12th case of a patient with a plasma cell granuloma of the thyroid, a rare cause of goiter and hypothyroidism.MethodsWe present a case report of a woman with a plasma cell granuloma of the thyroid. The clinical and pathologic features of the lesion are described, the differential diagnosis is discussed, and the relevant literature is reviewed.ResultsPlasma cell granulomas are uncommon benign lesions most typically located in the lung and only rarely identified in other organs. Only 11 cases of plasma cell granuloma of the thyroid gland have been reported previously. We describe the case of a 55-year-old woman with a long history of hypothyroidism and compressive symptoms from an enlarging neck mass. A thyroidectomy was performed. On gross examination, the thyroid had been replaced by firm, white, fibrotic tissue with a multinodular appearance. On microscopy, the infiltrate consisted predominantly of plasma cells that were polyclonal with the expression of both kappa and lambda light chains. A minor component of CD5- and CD20-positive (T and B) lymphocytes was observed. These features were important for establishing the diagnosis of a plasma cell granuloma and distinguishing the lesion from a plasmacytoma.ConclusionThis is the 12th reported case of plasma cell granuloma of the thyroid gland, a very rare cause of either a diffuse or a nodular goiter and hypothyroidism. The presence of a polyclonal plasma cell population with the expression of both kappa and lambda light chains helps to distinguish a plasma cell granuloma from a malignant plasmacytoma of the thyroid gland. (Endocr Pract. 2008; 14:611-617)     

Ganglioneuroma Manifesting as an Incidental Adrenal Mass in an Adult With Turner’s Syndrome

ObjectiveTo report a case of ganglioneuroma masquerading as an incidental adrenal mass in an adult patient with Turner’s syndrome.MethodsWe present the clinical, laboratory, radiologic, and pathologic findings in this patient.ResultsA 31-year-old woman with Turner’s syndrome who had previously been treated with growth hormone replacement had an incidentally discovered mass, apparently arising from the left adrenal gland. The mass was “silent” clinically and biochemically, but imaging characteristics were not reassuring for a benign cortical adenoma. Because of uncertainty regarding the nature of the mass, it was removed laparoscopically; during this procedure, it was noted to be intimately associated with, but anatomically distinct from, the left adrenal gland. The pathology report confirmed the presence of a benign ganglioneuroma.Conclusion: Although ganglioneuroma has previously been noted to be associated with Turner’s syndrome (especially in pediatric patients), to the best of our knowledge this is the first report of a ganglioneuroma manifesting as an incidental adrenal mass in an adult patient with Turner’s syndrome. (Endocr Pract. 2005;11:382-384)     

A Case of Adrenal Cavernous Hemangioma Presenting with Progressive Enlargement and Apparent Hormonal Hypersecretion

ObjectiveTo report the case of a man with an adrenal cavernous hemangioma presenting as a progressively enlarging adrenal mass with apparent hormonal hyper-secretion.MethodsWe report the clinical, laboratory, imaging findings, and clinical course of this patient, and we highlight the important atypical features of this case. The literature is reviewed for the typical presentations of adrenal cavernous hemangiomas.ResultsA 59-year-old man presented with an adrenal incidentaloma that had an imaging phenotype suggestive of a pheochromocytoma or an adrenal carcinoma. The hormonal profile also suggested a state of aldosterone and catecholamine hypersecretion. Surgery, however, proved the diagnosis to be an adrenal cavernous hemangioma.ConclusionAlthough adrenal cavernous hemangioma is a rare entity, it should be considered in the differential diagnosis of an adrenal incidentaloma. Its radiologic features are not specific, and the presence of hormonal hypersecretion does not exclude the diagnosis. (Endocr Pract. 2008;14:104-108)     

Cushing Syndrome in a Young Woman Due to Primary Pigmented Nodular Adrenal Disease

ObjectiveTo report a case of Cushing syndrome due to apparently sporadic primary pigmented nodular adrenal disease in a young woman.MethodsWe describe the clinical, biochemical, radiologic, and histologic findings of Cushing syndrome due to the rare condition of primary pigmented nodular adrenal disease.ResultsA 30-year-old woman presented with a 2-year history of worsening itch without rash over her shoulders and arms and weight gain, particularly around the abdomen and face. Careful questioning did not elicit any history of exogenous glucocorticoid use (systemic or topical), including hydrocortisone. On examination, the patient had a slightly rounded and plethoric face, a small buffalo hump, central adiposity, and thin skin with a few small striae on her inner thighs. No features of the Carney complex were observed. Investigations showed hypercor- tisolism with suppressed corticotropin and normal adrenal imaging despite documentation of enlarged adrenal glands at removal. High-dose dexamethasone administration was followed by a decrease in urinary free cortisol excretion rather than a paradoxical rise as previously reported in primary pigmented nodular adrenal disease. No mutations were detected in the PRKAR1A gene.ConclusionsPrimary pigmented nodular adrenal disease should be suspected in patients with corticotropinindependent Cushing syndrome who have normal adrenal imaging. The role of genetic testing in apparently sporadic cases is not established, but cumulative experience may be helpful in defining the frequency of PRKAR1A mutations. (Endocr Pract. 2010;16:84-88)     

Intravascular Lymphoma: an Unusual Diagnostic Outcome of an Incidentally Detected Adrenal Mass

ObjectiveTo describe a rare diagnosis of intravascular lymphoma in a patient presenting with an incidentally discovered adrenal mass.MethodsWe describe the patient’s clinical history and the findings from biochemical evaluation, radiologic studies, and surgical pathology and review the relevant literature.ResultsA 43-year-old woman developed sudden onset of flank pain associated with a flushing sensation and presented to the emergency department where computed tomography showed a 5-cm left adrenal mass. She had normal electrolytes, and serum and urinary test results were negative for pheochromocytoma. A 24-hour urinary cortisol level was minimally elevated, and the midnight salivary cortisol value was within the reference range. Magnetic resonance imaging revealed a 6.5 × 5.8-cm left adrenal lesion that demonstrated moderate T2-weighted signal and gradual delayed enhancement with no drop in signal on out-of-phase images. Since the lesion lacked high intensity and the biochemical testing results did not suggest a pheochromocytoma, it was deemed likely that the mass was a malignant lesion of the left adrenal gland. A laparoscopic left adrenalectomy was performed. Morphologic and immunohistochemical findings were consistent with a large B-cell lymphoma, which by virtue of its near exclusive distribution in vascular spaces, was consistent with the diagnosis of intravascular large B-cell lymphoma.ConclusionIntravascular large B-cell lymphoma should be included in the differential diagnosis of an incidentally detected adrenal mass even though the diagnosis is rare. (Endocr Pract. 2008;14:884-888)     

Endoscopic Ultrasound-Guided Fine-Needle Aspiration With Aspirate Assay to Diagnose Suspected Mediastinal Parathyroid Adenomas

ObjectiveTo describe our experience with mediastinal parathyroid adenomas diagnosed by endoscopic ultrasound-guided fine-needle aspiration (EUSFNA) and measurement of parathyroid hormone.MethodsWe describe the clinical and pathologic findings and diagnostic techniques used in 2 study patients.ResultsPatient 1 was a 54-year-old man with persistently elevated serum calcium and parathyroid hormone concentrations despite removal of a right inferior parathyroid adenoma. An echoendoscope was used to identify the lesion and to perform FNA. The parathyroid hormone concentration measured in the aspirated material was 1800 pg/mL. Pathologic examination of the resected specimen revealed a 29.7-g parathyroid adenoma. Patient 2 was an 86-year-old woman with recurrent hyperparathyroidism. A linear array echoendoscope was used to perform FNA of the lesion in her mediastinum. The parathyroid hormone concentration measured in the aspirated specimen was 6905 pg/mL.ConclusionsPreoperative localization of recurrent or persistent hyperparathyroidism is often difficult. EUSFNA allows evaluation of masses, such as those found in the mediastinum, that are poorly evaluated by other imaging modalities. This technique may be a useful adjunct in diagnosing mediastinal parathyroid adenomas. (Endocr Pract. 2010;16:437-440)     

Hyperandrogenism in a Postmenopausal Woman: Diagnostic and Therapeutic Challenges

ObjectiveTo describe a postmenopausal woman with severe hyperandrogenism who responded dramatically to a gonadotropin-releasing hormone (GnRH) agonist.MethodsDetailed clinical and laboratory findings are presented, and the pertinent literature is reviewed.ResultsA 53-year-old postmenopausal woman with end-stage renal disease, who had undergone kidney transplantation, was referred because of high serum testosterone levels. She presented with worsening acne and hirsutism for the previous 2 years. Her medications included prednisone (7.5 mg every other day). On examination, mild facial acne and hirsutism but no virilizing features were noted. Laboratory results showed generous postmenopausal gonadotropin levels and markedly elevated total and free testosterone levels, which failed to suppress with a 2-day low-dose dexamethasone test. Transvaginal ultrasonography and a computed tomographic scan failed to identify an ovarian or adrenal abnormality. Administration of a GnRH agonist (Depo-Lupron) resulted in a dramatic decline in follicle-stimulating hormone, luteinizing hormone, and testosterone levels after 1 month, which persisted during the course of 11 months of therapy. The source of marked hyperandrogenism in postmenopausal women represents a diagnostic challenge. The absence of a tumor on diagnostic imaging and the inability to perform catheterization studies confound the problem. Androgen levels did not suppress with glucocorticoids. We reasoned that a clear response to a GnRH agonist would indicate a nontumorous ovarian source of hyperandrogenism. Regrettably, the literature has described cases of ovarian tumors and, rarely, adrenal adenomas that are responsive to gonadotropins.ConclusionThe striking improvement in a postmenopausal woman with severe hyperandrogenism by means of GnRH agonist therapy demonstrates its potential use in poor surgical candidates without necessarily delineating the source of androgen excess. (Endocr Pract. 2011;17:e21-e25)     

Transformation of a Pituitary Macroadenoma into to a Corticotropin-Secreting Carcinoma Over 16 Years

ObjectiveTo describe a case of a pituitary macroadenoma that differentiated into a corticotropin (ACTH)-secreting carcinoma with metastasis to the thigh.MethodsWe present a case report with a 16-year follow-up that includes anatomic and endocrine documentation of the history of an ACTH-secreting carcinoma.ResultsA 32-year-old woman presented for evaluation in 1989 because of visual feld 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 insuffciency. 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.ConclusionA 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. (Endocr Pract. 2007;13:463-471)