Lipid degeneration in a pheochromocytoma histologically mimicking an adrenal cortical tumor.

A recurrent adrenal pheochromocytoma is reported in an 18-year-old woman with a family history of multiple endocrine neoplasia type IIA. The tumor was noteworthy for the presence of numerous fine intracytoplasmic lipid droplets confirmed by fat stain. Immunohistochemical studies revealed cytoplasmic positivity for chromogranin and neuron-specific enolase typical of pheochromocytoma. Electron microscopy demonstrated dense-core neurosecretory granules, in addition to the cytoplasmic lipid vacuoles. The presence of lipid within an adrenal pheochromocytoma is rare and, to our knowledge, has been documented in only one previous case report in the literature.