Answer: A
Histological Description:
Adjacent to the adrenal is a nodule with a biphasic appearance. There are nests of cells with abundant eosinophilic cytoplasm, indistinguishable from Leydig cells. Between these nests is a very cellular spindle cell proliferation composed of bland cells with elongated nuclei, no atypia, and no mitotic activity. These cells are identical to thecal cells seen in ovarian or testicular thecomas.

Discussion: In this case there is unremarkable adrenal tissue with an adherent nodule of thecal/Leydig cells. Stains were performed at the outside institution demonstrating that the Leydig cell component was positive for SF1 and synaptophysin. The spindle cell component was positive for SMA (patchy) and desmin (focal). Both were negative for PAX8, inhibin, calretinin, S100, CD34, HMB45, p63, and chromogranin. Additional stains were performed at Johns Hopkins showing that the Leydig cell component was focally positive for PR and the spindle cell component was diffusely positive for ER and PR. This case represents a rare entity which could be regarded as either “ovarian thecal metaplasia of the adrenal gland” or “benign sex cord stromal tumor/nodule” arising adjacent to the adrenal gland.” The adrenal cortex is derived from the intermediate mesoderm in the region between the genital ridge and the root of the mesentery, such that embryologically gonadal tissue fused with the adrenal would be feasible. It is much more common to see this close relationship of adrenal and gonadal tissue manifest with adrenal cortical tissue in the inguinal or testicular region, representing adrenal cortical tissue that descends with the testis from the abdomen down to the scrotum during fetal development.