Ovarian hilar proliferations resembling Sertoli cell tumours: microscopic neoplasms or non-neoplastic remnants?

AIMS: To describe four cases of incidentally detected microscopic ovarian hilar Sertoli cell proliferation, a phenomenon that, as far as we are aware, has not been previously reported, and to discuss the differential diagnosis of these lesions. METHODS AND RESULTS: The proliferations occurred in women aged 35-62 years, and were composed of solid and hollow tubules that were morphologically and immunohistochemically in keeping with Sertoli cells. Two cases were bilateral. CONCLUSIONS: We feel that these uncommon proliferations are likely to represent non-neoplastic embryological remnants rather than hilar Sertoli cell tumours.