GPT and duodenal neuroendocrine tumor, well differentiated, low or intermediate grade: In contrast, none of the other rare NF1-associated tumors demonstrated ALT (Additional file 1: Table S3), including gastrointestinal stromal tumors (GIST), pheochromocytomas, glomus tumors, juvenile xanthogranulomas, and duodenal neuroendocrine tumors.