Clear Cell Sarcoma-like Tumor of the Gastrointestinal Tract: Clinical Outcome and Pathologic Features of a Molecularly Characterized Tertiary Center Case Series.

BACKGROUND/AIM: Clear cell sarcoma-like tumor of the gastrointestinal tract (CCSLTGT) is a very rare and relatively recently characterized mesenchymal neoplasm arising within the wall of the small bowel, stomach, or large bowel, predominantly in adolescents and young adults. Only few anecdotal reports or small series have been published and a consensus on treatment has not been formulated. Complete resection remains the only curative option for localized disease, but despite optimal surgery, CCSLTGT typically shows highly aggressive behavior with a high rate of local recurrence, metastases, and death from disease. The hallmark of CCSLTGT is the presence of EWSR1-CREB1 or EWSR1-ATF1 gene fusions, detectable with reverse transcription-polymerase chain reaction (PCR). The aim of this study was to assess all referred cases of CCSLTGT, and document the pathological features, treatment and outcome of these patients. PATIENTS AND METHODS: We retrospectively reviewed all cases of histologically- and molecularly-confirmed CCSLTGT with EWSR1-CREB1 or EWSR1-ATF1 fusions at our tertiary sarcoma center, between 2009 and 2016. RESULTS: We assessed six patients diagnosed with CCSLTGT. In a median follow-up of 8 months, all patients received surgery, and additionally one patient was treated with chemotherapy and had progressive disease. Five of six patients experienced recurrence or progression of disease and 4 of 6 patients died of disease. CONCLUSION: Our study confirms that CCSLTGT is a very rare aggressive sarcoma subtype with a very poor outcome. Greater international collaboration is required to obtain a better understanding of this disease.