Skin lesions indicate cause of acute gastrointestinal bleeding: neurofibromatosis type 1

[...]a CT scan of the patient's abdomen showed a 3 cm diameter mass with soft tissue density in the proximal jejunum; a double balloon enteroscopy confirmed the presence of a tumour (figure). Detailed histopathological examination of a sample of the excised tumour showed spindle cells with mitotic activity, and immunohistochemical staining showed the spindle cells were c-kit and CD34 positive. Diagnosis is primarily based on the US National Institutes of Health diagnostic criteria: café-au-lait macules, neurofibromas, and Lisch nodules, and a positive family history of the disease.