Adenomatoid tumor of the adrenal gland: a report of four new cases and a review of the literature.

Adenomatoid tumors of the adrenal gland are rare, benign, asymptomatic neoplasms that are usually found incidentally. Previously reported cases occurred only in men and only on the left side. We report four cases, including two from the right adrenal gland, one from a woman, and one with a cystic component. The average age of our patients was 49 years, compared with the average age of 34 years in previously reported cases. Our immunohistochemical stains and electron microscopic analysis support the presumed mesothelial derivation of these tumors. The differential diagnosis of adenomatoid tumors of the adrenal gland includes a variety of solid and cystic tumors. It is important to recognize these rare tumors to avoid misclassifying them, especially as metastatic or primary malignant vascular tumors.