Although there are several reports of
Brenner tumor showing
estrogen activities, it is an extremely rare cause of
androgen excess leading to
virilism, and the source or mechanism of its
androgen production is also unknown at present. A 74-year-old woman presented with lower
abdominal pain and increased facial hair growth of 6-month duration. Bilateral ovarian
tumors were detected, and her serum
testosterone (1.7 ng/mL) and
estradiol (75 pg/mL) levels were elevated. Bilateral
salpingo-oophorectomy was performed. The ovarian
tumors were diagnosed as
benign Brenner tumor associated with fibrothecoma-like and luteinized stromal cells. Postoperatively, the serum
testosterone and
estradiol levels decreased. Immunohistochemically, fibrothecoma-like stromal cells were positive for
cytochrome P-450 aromatase, which catalyzes the conversion from
androgen to
estrogen, and negative for c-Jun
protein, which has recently reported to attenuate
estrogen biosynthesis by directly down-regulating transcription of the
aromatase gene. On the other hand, luteinized stromal cells were negative for
cytochrome P-450 aromatase and positive for c-Jun
protein. It is suggested that
androgen is produced mainly in the luteinized stromal cells, because
androgen is not converted to
estrogen caused by suppression of
aromatase biosynthesis by c-Jun.