This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Testicular Tumors, Subject name: Pathology
A middle aged adult undergoes orchiectomy. Looking at the gross and the histological findings, which of the following is the likely diagnosis? 
Select and explain. 
A. Lymphoma, B. Seminoma, C. Yolk sac tumor, D. Teratoma
B: Seminoma
Answer: B: Seminoma 
Explanation: Most common germ cell tumor seen in middle aged adults : seminoma Gross findings : Well circumscribed ;No hemorrhage, no necrosis M/E : Tumor cells have distinct cell membrane ;Clear or watery cytoplasm