Call-Exner body

**Definition/Histology:** Call-Exner bodies are small, round, gland-like spaces surrounded by granulosa cells, often arranged in a rosette or "follicle-like" pattern around eosinophilic material (basement membrane material/ proteinaceous fluid, PAS-positive). They are seen in about 50% of adult granulosa cell tumors. Nuclei are often "coffee-bean" shaped with longitudinal grooves.

**Associated tumor: Granulosa cell tumor (sex cord-stromal tumor)** - Derived from granulosa cells of the ovarian follicle. - Secretes **estrogen** (and **inhibin**, a useful tumor marker; also AMH). - Clinical features: - Precocious puberty in girls (isosexual). - In reproductive-age women: menstrual irregularities. - In postmenopausal women: postmenopausal bleeding. - Endometrial hyperplasia and **endometrial carcinoma** due to unopposed estrogen. - Breast tenderness/enlargement. - Large adnexal mass; can rupture and cause hemoperitoneum. - Most are low stage at diagnosis with good prognosis, but late recurrences can occur. - Treatment: surgery (hysterectomy/bilateral salpingo-oophorectomy, or unilateral oophorectomy for fertility preservation) +/- chemotherapy. - Molecular: FOXL2 C134W mutation in adult-type granulosa cell tumors.

**High-yield comparisons (ovarian sex cord-stromal tumors):** - Granulosa cell tumor: Call-Exner bodies, estrogen, inhibin. - Thecoma/fibroma: spindle cells; fibroma associated with **Meigs syndrome** (ovarian fibroma + ascites + right pleural effusion). - Sertoli-Leydig cell tumor: androgens, virilization, Reinke crystals (Leydig cells).

**Other buzzwords to differentiate:** - Schiller-Duval bodies: yolk sac tumor (AFP). - Psammoma bodies: serous cystadenocarcinoma. - Signet-ring cells: Krukenberg tumor. - Coffee-bean nuclei: granulosa cell tumor (also Brenner tumor, transitional cells).

**Mnemonic:** "Call-Exner = Cells of Estrogen (granulosa)". Think "Call (Exner) for estrogen."