An ovarian neoplasm composed of LUTEAL CELLS derived from luteinized GRANULOSA CELLS and THECA CELLS. Luteomas respond to GONADOTROPINS, and vary in their hormone production (PROGESTERONE; ESTROGENS; or ANDROGENS). During PREGNANCY, a transient type of luteoma may develop due to an exaggerated LUTEINIZATION of the OVARY.

Neoplasms derived from the primitive sex cord or gonadal stromal cells of the embryonic GONADS. They are classified by their presumed histogenesis and differentiation. From the sex cord, there are SERTOLI CELL TUMOR and GRANULOSA CELL TUMOR; from the gonadal stroma, LEYDIG CELL TUMOR and THECOMA. These tumors may be identified in either the OVARY or the TESTIS.

The co-occurrence of pregnancy and NEOPLASMS. The neoplastic disease may precede or follow FERTILIZATION.