Multiple Gastric Gastrointestinal Stromal Tumors in a Patient with Neurofibromatosis Type 1.

Gastrointestinal stromal tumors (GISTs) are relatively common in neurofibromatosis type 1 (NF 1) patients. Approximately 90% of GISTs associated with NF 1 are located in the small intestine, while sporadic GISTs are most commonly located in the stomach. Here we report an extremely rare case of an NF 1 patient with multiple gastric GITs (90 or more) but without multiple small intestinal tumors. A 63-year-old female patient who had a history of NF 1 underwent surgery for a gastric neuroendocrine tumor and gastric submucosal tumor (SMT). During the operation, multiple small nodules were identified on the serosal surface of the upper stomach. SMT and multiple nodules on the serosal surface were diagnosed as GISTs consisting of spindle cells positive for KIT, CD34, and DOG-1. Both GIST and the normal gastric mucosa showed no mutations not only in the c-kit gene (exons 8, 9, 11, 13, and 17) but also in the PDGFRA gene (exons 12, 14, and 18). This patient is being followed up without the administration of a tyrosine kinase inhibitor.