Inhibin as a marker for granulosa cell tumor

In order to determine whether serum-immunoreactive inhibin could constitute a biochemical marker for the presence and progression of ovarian granulosa cell tumors and their metastases, we measured immunoreactive inhibin concentrations in series of serum samples obtained from 8 patients with granulosa cell tumor. Six series were tested in retrospect. From these, three came from patients who had been treated with an abdominal hysterectomy and bilateral salpingo-oophorectomy. In the 2 patients with residual or recurrent disease, inhibin was elevated, 4 and 20 months respectively before clinical manifestations of recurrence became evident; it reflected the effects of secondary therapy. Inhibin remained undetectable in one patient who was free of disease during 11 years of follow-up. Inhibin concentrations were also inappropriately increased in 2 of 3 women with amenorrhea and infertility resulting from small granulosa cell tumors. After removal, inhibin concentrations became normal and fertility resumed. Fertility also returned in the third patient. There was a significant negative correlation between the serum inhibin and FSH concentrations, consistent with autonomous production of inhibin by granulosa cell tumors. It is concluded that granulosa cell tumors have the capacity to produce inhibin. In retrospect, inhibin proved to be a marker for both primary and also recurrent and residual disease.