Image Description
Yolk sac tumor (YST) in adults has to be differentiated from primary ovarian carcinomas.
Clear Cell Carcinoma (CCC): CCC shows tubular, cystic, and papillary growth patterns; presence of endometriosis in the background favors CCC; positivity for CK7, EMA, and PAX8; negative for AFP, glypical-3, and SALL4; reticular/microcystic/polyvesicular areas and Schiller-Duval bodies favors YST
Endometrioid Carcinoma (EC): EC will show other components such as squamous and mucinous areas; background of endometriosis; YST with endometrioid pattern shows greater pleomorphism and mitotic activity than EC.
Dysgerminoma: Solid YST can closely resemble dysgerminoma. Features favoring YST include - greater nuclear pleomorphism, positivity for cytokerain, AFP, and glypican-3. Features favoring dysgerminoma include inflammatory cells in the fibrous septae and positivity for OCT4.
About the Disease
Germ cell tumors (GCT) of the ovary originate from primordial germ cells and make up 30% of all primary ovarian neoplasms. More than 90% of ovarian GCT are mature cystic teratomas which are benign tumors. Remaining 5% are malignant. Malignant GCT make up 3% and 20% of all ovarian cancers in Western countries and Asian/African countries respectively. Patients with malignant GCT are usually between 15-30 yrs. of age. Tumors are large (average size 16 cm) and generally unilateral (except dysgerminomas; 10-20% cases are bilateral). Presenting symptoms are abdominal enlargement and pelvic pain. Serum hCG and AFP levels can give a clue to the diagnosis and are useful in monitoring postoperatively. The treatment consists of fertility-sparing surgery followed by combination chemotherapy. About 60-75% of patients present with Stage I disease which has a cure rate of almost 100%. About 25-30% have Stage III disease at diagnosis and the cure rate is around 75%. REFERENCES: 1. WHO Classification of Tumors. Female Genital Tumors. 5th Edition, 2020; IARC, Lyon, France. 2. Nucci MR, Parra-Herran C (2021). Gynecologic Pathology. 2nd Edition. Philadelphia, PA. Elsevier. 3. Goldblum, J. R. et al (2018). Rosai and Ackerman's Surgical Pathology - Eleventh Edition. Philadelphia, PA. Elsevier.