Primary amenorrhea revealing an occult progesterone-secreting ovarian tumor.

Objective: To describe a patient with primary amenorrhea revealing an occult progesterone-secreting ovarian tumor.
Design: Case report.
Setting: University medical center.
Patient(s): A 20-year-old woman with primary amenorrhea.
Intervention(s): Investigations to identify the source of progesterone secretion.
Main Outcome Measure(s): Discovery of an occult progesterone-secreting ovarian tumor.
Result(s): Initial ovarian ultrasonography did not show any abnormal mass. Catheterization of ovarian veins suggested a right ovarian source of progesterone. After long-term follow-up, a right ovarian tumor became apparent and was surgically removed. After surgery, progesterone levels decreased and normal ovulatory cycles resumed. Pathologic and immunohistochemical analysis showed a Leydig cell tumor expressing cytochrome P450 side-chain cleavage and 3ss-hydroxysteroïd dehydrogenase enzymes, which are involved in progesterone biosynthesis, whereas P45017alpha-hydroxylase was not expressed, explaining the absence of hyperandrogenemia. Before surgery, two LH pulses were detected during a 6-hour study period and a lack of ovarian response to pulsatile GnRH administration.
Conclusion: This is the first case of isolated progesterone secretion by an occult ovarian Leydig cell tumor and a novel etiology of primary amenorrhea. The results also suggest that sustained progesterone can exert an inhibitory effect on gonadotropin secretion at both hypothalamic and pituitary levels.