A 25-year-old woman is found to have a 6 cm unilateral ovarian mass containing cells with Call-Exner bodies on histology. AFP is normal, LDH is normal, but estradiol is elevated at 400 pg/mL. She has menstrual irregularity and endometrial hyperplasia. What is the diagnosis, and what is the associated FOXL2 mutation?
- A Adult granulosa cell tumor with FOXL2 402C→G (C134W) missense mutation ✓
- B Juvenile granulosa cell tumor with isochromosome 12p
- C Sertoli-Leydig cell tumor with DICER1 mutation
- D Fibrothecoma with no specific molecular mutation
Explanation
Adult granulosa cell tumor (AGCT) is a sex cord-stromal tumor characterized histologically by Call-Exner bodies (small follicle-like structures with eosinophilic fluid surrounded by granulosa cells). AGCTs secrete estrogen, causing endometrial hyperplasia and menstrual irregularity. The pathognomonic molecular finding is the FOXL2 somatic missense mutation c.402C>G (p.C134W), present in >97% of AGCTs. This transcription factor mutation is highly specific for AGCT and distinguishes it from juvenile GCTs (which are FOXL2 wild-type and occur in prepubertal girls). Juvenile GCT has isochromosome 12p. Sertoli-Leydig cell tumors characteristically harbor DICER1 mutations. FOXL2 C134W is a pathognomonic mutation for NEET examination purposes.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.