Adenomatous hyperplasia of the rete testis.

A gland-like cellular proliferation was observed in the deepest portion of the rete testis in both testes from a 55-year-old man who died from metastasis of breast carcinoma to the brain. The gland-like proliferations consisted of columnar epithelial cells supported by a thin lamina propria. These cells displayed irregularly outlined nuclei with deep indentations. Atypias and mitoses were infrequent. The term 'adenomatous hyperplasia of the rete testis' is proposed to designate the benign lesion reported here.