Thecal metaplasia in the adrenal gland of a man with acquired bilateral testicular atrophy.

Thecal metaplasia of the adrenal was observed as an incidental autopsy finding in a 77-year-old man with acquired bilateral testicular atrophy, probably secondary to previous bilateral inguinal herniorrhaphy. The metaplastic focus was composed of interlacing bundles of spindle cells attached to the adrenal capsule, strongly resembling ovarian theca. A related finding was hyperplasia of the anterior pituitary, involving particularly the basophils. We believe that the acquired gonadal failure of this man may have led to increased activity of the pituitary gonadotropes. Blastema cells outside of the testes with the ability to form gonadal stroma, such as cells of the adrenal capsule, were thereby stimulated to undergo metaplasia, giving rise to ovarian theca. Similar thecal metaplasia has been described previously in the adrenals of postmenopausal women. Whether the metaplastic foci are capable of hormone production is not known. Since this patient had an occult prostatic carcinoma at autopsy, potential hormone production by such metaplastic gonadal stroma is clinically relevant.