A sporadic multiple gastrointestinal stromal tumor with unique clinical and molecular features.

Most sporadic gastrointestinal stromal tumors occur as solitary lesions, whereas a multicentric appearance involving the stomach, the small intestine, or both sites is suspicious for lesions developed in the setting of hereditary or idiopathic tumor syndromes or metastatic disease. The rare occurrence of multiple sporadic gastrointestinal stromal tumors has been recently reported in the literature. Here, we report a case of multiple sporadic gastrointestinal stromal tumors affecting the small intestine in a 61-year-old man, unique with regard to the number of lesions (>30) and the molecular profile. Four different mutations of KIT involving exons 11, 13, and 17 were present among 4 of 10 excised tumors. In addition, BRAF p.V600E mutation was detected in 5 tumors and was mutually exclusive with KIT mutations. To our knowledge, this is the first time a case of a synchronic multisporadic gastrointestinal stromal tumor outstanding for the high number of lesions, which are of independent origin, is reported.