Adenomatoid Tumor of the Adrenal Gland

Pathology Page Adenomatoid Tumor of the Adrenal Gland denomatoid tumors are benign neoplasms of mesothelial derivation and are usually found in the male and female genital tract. Extragenital adenomatoid tumors have been identified in many sites including the pancreas, heart, pleura, intestinal mesentery, omentum, lymph nodes and hernia sac peritoneum. Less than 2 dozen tumors have been reported in the adrenal gland.1–3 The mesothelial origin of adenomatoid tumors is well documented. However, since the adrenal is not invested by mesothelium, the occurrence of adenomatoid tumors in the adrenal is not readily explained. It has been postulated that adrenal adenomatoid tumors arise from mesothelial cysts/inclusions or pluripotent mesenchyme associated with the müllerian tract.2,3 The latter is favored. Adenomatoid tumors occur in adults, the majority of whom are between 30 and 50 years old with a male preponderance.1–3 Typically these tumors produce no symptoms, are unassociated with any specific physical or laboratory abnormalities and are almost always incidentally discovered during radiological or surgical procedures, or at autopsy.2 One patient presented with hematuria attributed to compression of the superior pole of the kidney by an adrenal mass.2 Radiologically adrenal adenomatoid tumors are usually solid but rarely may be extensively cystic.3 Grossly adrenal adenomatoid tumors are typically smooth, pale and firm, and range from 0.5 to 11.0 cm in diameter. They may be discrete or poorly circumscribed, solid or cystic (fig. 1). Microscopically the tumor cells may form solid nests, but more often they form fenestrated channels and anastomosing tubules of variable size and shape set in a fibrous stroma of variable prominence. The cells lining these luminal structures range from plump epithelioid cells to flattened cells resembling endothelial cells. Many tumor cells have prominent vacuolization and in some cases may have a signet-ring appearance with apparent intracytoplasmic lumina. Typically the tumor cells infiltrate between and around existing residual adrenal cortical or medullary tissue, imparting an appearance of an infil-

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FIG. 2. Adrenal adenomatoid tumor composed of luminal structures diffusely intermingled with residual adrenal cortical tissue. Tumor cells show positive immunostaining for calretinin (inset).

trative growth pattern, and involvement of adrenal capsule or extension into peri-adrenal soft tissues is often noted (fig. 2).1–3 Nonetheless, the tumor cells lack nuclear pleomorphism, tumor necrosis and mitotic activity. Considering its rareness, architectural and cytologic variability, and apparent infiltrative growth pattern, it is not surprising that adrenal adenomatoid tumor may be difficult to distinguish from other neoplasms including adrenocortical adenoma or carcinoma, lymphangioma, hemangioma, angiosarcoma and metastatic adenocarcinoma, especially signet-ring cell adenocarcinoma. This distinction may be particularly difficult to make on frozen section or limited fine needle aspiration samples.2 Tumor cells show immunopositivity for calretinin (a marker of mesothelial derivation, fig. 2, inset) and several keratin markers but no immunoreactivity for vascular markers. Treatment of these benign neoplasms is surgical removal. Of the reported cases with followup none has recurred.1–3 Their clinical significance lies in the difficulty involved in recognizing their true nature, and distinguishing them from primary adrenal malignancies and metastatic cancers. Christina M. Wojewoda, Jay K. Wasman and Gregory T. MacLennan Institute of Pathology University Hospitals of Cleveland Case Western Reserve University Cleveland, OH REFERENCES 1.

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3. FIG. 1. Poorly circumscribed adrenal adenomatoid tumor with solid pale cut surface. 0022-5347/08/1803-1123/0 THE JOURNAL OF UROLOGY® Copyright © 2008 by AMERICAN UROLOGICAL ASSOCIATION

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Raaf HN, Grant LD, Santoscoy C, Levin HS and Abdul-Karim FW: Adenomatoid tumor of the adrenal gland: a report of four new cases and a review of the literature. Mod Pathol 1996; 9: 1046. Isotalo PA, Keeny GL, Sebo TJ, Riehle DL and Cheville JC: Adenomatoid tumor of the adrenal gland: a clinicopathologic study of five cases and review of the literature. Am J Surg Pathol 2003; 27: 969. Garg K, Lee P, Ro JY, Qu Z, Troncoso P and Ayala AG: Adenomatoid tumor of the adrenal gland: a clinicopathologic study of 3 cases. Ann Diagn Pathol 2005; 9: 11. Vol. 180, 1123, September 2008 Printed in U.S.A. DOI:10.1016/j.juro.2008.06.069