This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnosis in Obstetrics, Subject name: Gynaecology & Obstetrics
Sex cord ovarian tumors are all except - 
Select and explain. 
A. Teratoma, B. Granulosa cell tumors, C. Thecoma, D. Sertoli - Leydig cell tumors
A: Teratoma
Answer: A: Teratoma 
Explanation: Ans. is 'a' i.e., Teratoma o Primary ovarian tumors are further divided into three typesi) Surface epithelial tumorsii) Germ cell tumorsiii) Sex cord stromal tumorsSurface epithelial tumorsGerm cell tumorsSex cord stromal tumorso Serous tumoro Teratomao Thecomao Mucinous tumoro Dysgerminomao Fibromao Endometrial tumoro Endodermal sinus tumoro Granulosa-theca cell tumoro Clear cell tumoro Choriocarcinomao Sertoli-leydig cell tumoro Brenner tumor o Hilus cell tumorso Cysadenofibroma o Most ovarian tumors (65-70%) are surface epithelial tumors, most common being serous tumors (serous cystadenoma and cystadenocarcinoma).