A 40-year-old woman is evaluated for intermittent headaches, insomnia, diaphoresis, and unintentional weight loss over the past several months. The patient has no other medical problems and takes no medications. She does not use tobacco, alcohol, or illicit drugs and has no significant family history. The patient is found to have a neoplastic mass producing excessive amounts of hormones that are causing her symptoms. Surgical resection of the abnormal tissue is performed with no operative complications. Microscopic examination of the tumor cells shows electron-dense, membrane-bound secretory granules. Immunohistochemistry is positive for synaptophysin, chromogranin, and neuron-specific enolase. The abnormal tissue most likely originated from which of the following?

Question

A 40-year-old woman is evaluated for intermittent headaches, insomnia, diaphoresis, and unintentional weight loss over the past several months.  The patient has no other medical problems and takes no medications.  She does not use tobacco, alcohol, or illicit drugs and has no significant family history.  The patient is found to have a neoplastic mass producing excessive amounts of hormones that are causing her symptoms.  Surgical resection of the abnormal tissue is performed with no operative complications.  Microscopic examination of the tumor cells shows electron-dense, membrane-bound secretory granules.  Immunohistochemistry is positive for synaptophysin, chromogranin, and neuron-specific enolase.  The abnormal tissue most likely originated from which of the following?

Quizplus · Accepted Answer

11ec160b_3ac7_b2a8_9249_bb2ad2a1bd2b_MD0001_00 Pheochromocytoma is a tumor of the chromaffin cells of the adrenal medulla characterized by excess production of catecholamines (norepinephrine, epinephrine, dopamine). Fluctuating catecholamine release results in increased vascular tone and hypertension, often associated with episodic headache, diaphoresis, and palpitations. The diagnosis is confirmed by detecting elevated levels of urinary and plasma catecholamines and metanephrines (catecholamine breakdown products). Histopathology shows a highly vascular tumor with nests of spindle-shaped or polygonal cells. The neurohormonal character of the cells is confirmed with stains for synaptophysin, chromogranin, and neuron-specific enolase, and electron microscopy may show dense membrane-bound granules containing catecholamines. (Choices A and C) Syndromes associated with steroid hormone-producing tumors of the adrenal cortex include hypercortisolism (Cushing syndrome), hyperaldosteronism (hypertension, hypokalemia, metabolic alkalosis), and hyperandrogenism (hirsutism, acne, androgenetic hair loss). Metabolically active ovarian tumors also can cause hyperandrogenism. Overproduction of steroid hormones is apparent on electron microscopy as well-developed smooth endoplasmic reticulum rather than membrane-bound secretory granules. (Choice D) Parathyroid adenomas (or carcinomas) cause primary hyperparathyroidism resulting in hypercalcemia. Characteristic symptoms include constipation, abdominal pain, bone pain, and neuropsychiatric symptoms. (Choice E) Toxic nodular thyroid disease could produce this patient's symptoms (eg, diaphoresis, weight loss). However, metabolically active thyroid adenomas typically show a follicular structure, with uniform cells and large amounts of follicular colloid. Educational objective: Pheochromocytoma is a tumor arising from the chromaffin cells of the adrenal medulla characterized by excess production of catecholamines. Clinical features include episodic hypertension, diaphoresis, and palpitations. Microscopic examination of the tumor cells shows electron-dense, membrane-bound secretory granules, and immunohistochemistry is positive for synaptophysin, chromogranin, and neuron-specific enolase. __________ References: Pheochromocytoma and paraganglioma: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/24893135)

A 40-Year-Old Woman Is Evaluated for Intermittent Headaches, Insomnia, Diaphoresis