A case of multiple gastrointestinal stromal tumors caused by a germline KIT gene mutation (p.Leu576Pro).

Multiple gastrointestinal stromal tumors (GISTs) caused by germline KIT gene mutations are an extremely rare autosomal dominant disorder. We report a case of a 21-year-old woman who presented to the emergency department with a 2-week history of asthenia, palpitations and upper gastrointestinal bleeding. After further clinical evaluation one gastric and two small bowel GISTs were diagnosed, which were surgically resected after neoadjuvant therapy with Imatinib. Diffuse hyperplasia of the interstitial cells of Cajal was also seen in the background gastric and small intestinal walls. Somatic mutational analysis of the KIT gene revealed a substitution at codon 576 in exon 11 (p.Leu576Pro) in all tumors and normal ileal mucosa. The germline nature of this mutation was confirmed by mutation analysis in peripheral blood leukocytes. However, she had no familial history of GISTs and her parents did not carry the respective germline mutation.