Seminoma presenting as a solitary metastasis in gastric mucosa with regressed testicular mass

Gastric involvement by seminoma is extremely rare and all the reported cases were associated with bulky retroperitoneal disease or occurred late as part of advanced disease. We report a unique case of seminoma presenting as gastric mucosal metastasis. The diagnosis of this case was complicated by no residual testicular tumor or pelvic/retroperitoneal lymph nodes metastasis and no available specific serum markers. The histological morphology and immunostains allowed the correct diagnosis to be made in this case. This case highlights the rare manifestation of seminoma, which appears to be a primary tumor of an unusual site of germ cell tumor metastasis.