Luteinized adult granulosa cell tumor--a series of 9 cases: revisiting a rare variant of adult granulosa cell tumor.

Most adult granulosa cell tumors (AGCTs) consist of small-to-medium cells with scanty cytoplasm imparting a "small blue cell" appearance. We report 9 cases of luteinized AGCT, whose appearance differs from typical AGCT by the presence of abundant eosinophilic cytoplasm in at least 50% of tumor cells. These tumors were identified in patients aged between 37 and 80 years, all but 1 of whom were postmenopausal. The tumors ranged in size from 4.4 to 14 cm, usually had a yellow cut surface, were unilateral in 7 cases, bilateral in 1 case, and presented as a pelvic mass posthysterectomy in 1 case. Endometrial proliferative changes were present in 7 of 7 (100%) of the postmenopausal patients, a higher percentage than that reported in typical AGCT. The luteinized component occupied 50% to 90% of the tumors that were examined. Morphologic differences from typical AGCT were the luteinization of cytoplasm, relative lack of nuclear grooves, the presence of prominent nucleoli, and a myxoid stroma. The luteinized areas, especially when widespread, resulted in consideration of a wide range of other primary and metastatic ovarian neoplasms containing oxyphilic cells. Immunohistochemistry was useful in confirming a sex cord-stromal tumor, but of no value in the distinction from other neoplasms in the same category. Pathologists should be aware of the existence of luteinized AGCT, an uncommon variant of AGCT, to avoid an erroneous diagnosis.