[Gastrointestinal stromal tumor (GIST) in a patient with neurofibromatosis type 1. Report of one case].

Neurofibromatosis Type 1 (NF1) is an autosomic dominant condition affecting the central nervous system and presenting a disposition towards development of gastrointestinal stromal tumors (GIST). We report a 38 year-old female patient with neurofibromatosis type 1 that required emergency surgery due to a perforated GIST originating in the fourth duodenal portion. The GIST, and the fourth duodenal portion, were excised and a primary duodenum-jejunal anastomosis was performed. The pathological study showed a partially necrotic solid-cystic tumor with 1 to 2 mitoses per 50-high-power fields. The cells stained positively to CD 117, CD34 and Desmin, and were negative to S-100, Vimentin, and Smooth Muscle a-Actin. The patient is currently asymptomatic and under follow-up during the last 11 months after surgery.