Clear cell sarcoma of the stomach

Aim: Clear cell sarcoma is a high-grade sarcoma with morphological features resembling malignant melanoma. This tumour is reported to display a characteristic distribution pattern nearly always involving the extremities. We report the first case of clear cell sarcoma of the stomach. Methods and results: A 30-year-old male developed a huge tumour of the stomach, which at first glance could be considered as a poorly differentiated carcinoma. Immunohistochemical and ultrastructural examinations were consistent with a diagnosis of metastatic melanoma. However, cytogenetic examination revealed a t(12;22) translocation, specific for clear cell sarcoma. This was confirmed by fluorescence in-situ hybridization. Conclusion: Making a reliable diagnosis of clear cell sarcoma of the stomach requires cytogenetic or molecular diagnostic investigations, particularly to rule out metastatic melanoma. This diagnosis avoids an unnecessary search for a primary melanoma.