Luteoma of pregnancy consists of a well-circumscribed proliferation of luteinized cells with abundant eosinophilic cytoplasm and centrally placed round nuclei with prominent nucleoli. The stroma is scant and largely obscured by the luteinized cells.

A higher power demonstrates the luteinized cells with round uniform nuclei containing prominent nucleoli. Mitotic figures are not uncommon, although none were easily identified in this particular case.

A different case demonstrates a similar proliferation of luteinized cells. Note that there are several small poorly-formed lumens. Occasionally, follicle-like spaces (usually larger than shown in this image) containing eosinophilic secretions may be seen.

A higher power of the above example demonstrates round to ovoid nuclei with mild size variation and prominent nucleoli.

The lesion shows a brown-yellow appearance consistent with a luteinized entity.

Luteomas of pregnancy are uncommon benign hyperplastic nodules that develop during pregnancy and regress during the puerpartum period.

80% of patients are black, and the majority are multiparous. Most patients are asymptomatic and ovarian enlargement is found during caesarean sections or tubal ligation. 25% of patients exhibit virilization, and ~70% of female infants born to virilized mothers are themselves virilized. Plasma testosterone and androgens are significantly elevated.

Grossly, the luteomas range from microscopic to over 20 cm. In half the cases, there are multiple nodules within the ovary. In a third of cases, the luteomas are bilateral.

Excellent; other than endocrinologic manifestations (virilization) during pregnancy, the lesion is completely benign.