This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Testis & Scrotum, Subject name: Surgery
Which of the following is a retention cyst? 
Select and explain. 
A. Sebaceous cyst, B. Spermatocele, C. Dermoid cyst, D. Pancreatic cyst
B: Spermatocele
Answer: B: Spermatocele 
Explanation: Ans. b (Spermatocele). (Ref. Bailey and Love, 25th/1383)SPERMATOCELE is unilocular retention cyst, derived from epidydymis.CLASSIFICATION OF CYSTSA. Congenital (Persistence of normal vestigial remnants)1. Nuchal, thyroglossal, branchial.2. Ectopia of various tissues3. Failure of continuation of tubular element.4. Hamartomas5. Hydatid of morgagni6. Dermoid, epidermoid, enterogenous7. PCKD8. Cystic hygroma, omental cystB. Acquired1. Mucus retention cyst3. Parasitic5. Degenerative7. Apoplectic (not a true cyst)9. Pseudocyst11. Epidermoid/sebaceous13. Mammary dysplasia15. Hematogenous cyst17. Cystadenoma, cystic teratoma2. Implantation cyst4. Hyperplastic6. Traumatic8. Neoplastic10. Spermatocele, Retention cyst of mouth12. Hydatid, trichinosis14. Uterine leiomyoma16. Pituitary18. Pancreas