Testicular Gastrointestinal Stromal Tumor (GIST): An Extremely Unusual Secondary of Gastric Primary

A 21 year old male presented with a swelling in the right testicular region for the past 2 months. Serum tumor markers were within normal limits. Fine needle aspiration from right testis (8x6cms) revealed plasmacytoid to epithelioid cells with necrosis. The patient had a distal gastrectomy 5 years back, which was diagnosed as gastrointestinal stromal tumor (GIST) with high malignant potential and was on continuous imatinib therapy from the time of diagnosis till two years, however, at present was off and on therapy. Varied differential diagnosis were kept considering morphology, however, in view of the past history, cytological diagnosis was given as metastatic GIST. Orchidectomy specimen showed features of epithelioid GIST (CD117 and CD34 positive expression). A final diagnosis of metastatic epithelioid GIST to the testis was thus rendered. This case is being discussed due to rarity of metastatic GIST in testis with an emphasis on the differential diagnosis.