Multiple gastrointestinal stromal tumors with exon 11 mutation of the c-KIT gene in a young male without family history.

Multiple gastrointestinal stromal tumors (GISTs) are extremely rare, usually related to specific tumor syndromes such as familial GIST syndrome, neurofibromatosis type 1 (NF1), and the Carney triad. A 27-year-old man came to the hospital for treatment due to watery bloody stool. Abdominal CT disclosed multiple tumors in the gastrointestinal tract. The postoperative pathological examination showed multiple GISTs and diffuse hyperplasia of interstitial cells of Cajal. The c-KIT mutation at exon 11 c.1676T>C (p.V559A) was detected in the paraffin-embedded tumor tissue. He had skin hyperpigmentation from childhood, but had no family history of GIST. This case of multiple GISTs without family history attracted our attention.