The most common symptom is a progressive, painless enlargement of the testicle with a feeling of heaviness. Enlarged testes in spermatogenic tumors tend to maintain the contour of the testicle and have a uniform texture, whereas teratomas are nodular and enlarged with inconsistent hardness and tenderness. About 10% of patients feel pain due to intra-testicular hemorrhage or infarction. 10% of patients may have metastatic symptoms, such as a large retroperitoneal lymphatic metastasis that compresses a nerve root and presents with back pain. Pulmonary metastases may present with cough and dyspnea, duodenal metastases may present with anorexia, nausea and vomiting, and bone metastases may cause bone pain, etc. Testicular mesenchymal cell tumor should be considered in children with testicular masses along with symptoms of precocious puberty, or in adults with gynecomastia and decreased libido.