Pregnancy luteoma with granulosa cell proliferation: An unusual hyperplastic lesion arising in pregnancy and mimicking an ovarian neoplasia

A pregnancy luteoma (PL) was incidentally found at a term cesarean section in a 27-year-old black woman without any endocrine abnormality. The lesion involved only the left ovary; it had a nodular and focal pseudoalveolar growth pattern and was associated with areas of tubular sertoliform component, consistent with granulosa cell proliferation. Immunohistochemistry revealed a diffuse positivity to Inhibin A, CD99, cytokeratin and vimentin. The ultrastructure was typical of steroid-producing cells. PL is a tumor-like lesion arising in pregnant women and often misdiagnosed as a neoplastic lesion; awareness of this rare entity and its differential diagnoses may avoid unnecessary surgery in young patients.