Struma Ovarii : Differential Diagnosis

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.