What is a pheochromocytoma, what are the life-threatening complications of pheochromocytomas, where are pheochromocytomas most commonly located, and what is the likelihood of malignancy in pheochromocytoma?

Updated: Jul 20, 2020
  • Author: Michael A Blake, MBBCh, MRCPI, FRCR; Chief Editor: George T Griffing, MD  more...
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Answer

A pheochromocytoma (see the image below) is a rare, catecholamine-secreting tumor derived from chromaffin cells. The term pheochromocytoma (in Greek, phios means dusky, chroma means color, and cytoma means tumor) refers to the color the tumor cells acquire when stained with chromium salts.

Axial, T2-weighted magnetic resonance imaging (MRI) scan showing large left suprarenal mass of high signal intensity on a T2-weighted image. The mass is a pheochromocytoma.

About 30% of pheochromocytomas occur as part of hereditary syndromes. Although pheochromocytoma has classically been associated with 3 syndromes—von Hippel-Lindau (VHL) syndrome, multiple endocrine neoplasia type 2 (MEN 2), and neurofibromatosis type 1 (NF1)—there are now 10 genes that have been identified as sites of mutations leading to pheochromocytoma. These different genes produce tumors with different ages of onset, secretory profiles, locations, and potential for malignancy.5Därr R, Lenders JWM, Hofbauer LC, Naumann B, Bornstein SR, Eisenhofer G. Pheochromocytoma: Update on Disease Management. Ther Adv in Endo and Metab. 2012;3(1):11-26.

Because of excessive catecholamine secretion, pheochromocytomas may precipitate life-threatening hypertension or cardiac arrhythmias. [6] If the diagnosis of a pheochromocytoma is overlooked, the consequences can be disastrous, even fatal; however, if a pheochromocytoma is found, it is potentially curable. (See Pathophysiology, Prognosis, and Treatment.)1Waguespack SG, Rich T, Grubbs E, Ying AK, Perrier ND, Ayala-Ramirez M, et al. A current review of the etiology, diagnosis, and treatment of pediatric pheochromocytoma and paraganglioma. J Clin Endocrinol Metab.

About 85% of pheochromocytomas are located within the adrenal glands, and 98% are within the abdomen. When such tumors arise outside of the adrenal gland, they are termed extra-adrenal pheochromocytomas, or paragangliomas.

Extra-adrenal pheochromocytomas develop in the paraganglion chromaffin tissue of the nervous system. They may occur anywhere from the base of the brain to the urinary bladder. Common locations for extra-adrenal pheochromocytomas include the organ of Zuckerkandl (close to the origin of the inferior mesenteric artery), bladder wall, heart, mediastinum, and carotid and glomus jugulare bodies. (See Workup.)

Malignancy

Approximately 10% of pheochromocytomas and 35% of extra-adrenal pheochromocytomas are malignant. Only the presence of metastases defines malignancy. However, specific histologic features help to differentiate adrenal pheochromocytomas with a potential for biologically aggressive behavior from those that behave in a benign fashion. Among the features that suggest a malignant course are large tumor size and an abnormal DNA ploidy pattern (aneuploidy, tetraploidy).6Thompson LD. Pheochromocytoma of the Adrenal gland Scaled Score (PASS) to separate benign from malignant neoplasms: a clinicopathologic and immunophenotypic study of 100 cases. Am J Surg Pathol.  Common metastatic sites include bone, liver, and lymph nodes.

For discussion of pheochromocytoma in children, see the Medscape Drugs & Diseases article Pediatric Pheochromocytoma.7Bholah R, Bunchman TE. Review of Pediatric Pheochromocytoma and Paraganglioma. Front Pediatr.


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