Synchronous Upper Intestinal Neurofibromas and Duodenal Periampullary Well-Differentiated Neuroendocrine Tumor Associated With Neurofibromatosis 1

Abstract

Neurofibromatosis type I (NF1) is an autosomal dominant genetic disorder associated with characteristic skin findings, as well as a fourfold increase in risk of malignancy. NF1 patient malignancies commonly include the central and peripheral nervous system, but these patients are also at high risk of developing gastrointestinal (GI) tumors. While most often these GI tumors are benign upper GI neurofibromas; clinicians should have a high suspicion for malignant tumors, degeneration into a malignant peripheral nerve sheath tumor or less common associated malignancies such as well-differentiated neuroendocrine tumor (formerly carcinoid tumor), when patients present with multiple GI tumors. Our patient underwent a Whipple for symptomatic neurofibromas associated with NF1 and was unexpectedly discovered to have a metastatic duodenal well-differentiated neuroendocrine tumor. The patient is a 66-year-old man with NF1 who presented with hematemesis and was found to have large gastric neurofibromas and an ampullary neurofibroma based on endoscopy and radiological imaging. Another ostensive neurofibroma was noted distally. A pancreatoduodenectomy was performed. Pathological examination identified the neurofibromas but the tumor measuring 1.4cm and arising from the minor duodenal papilla was, in fact, a synchronous well-differentiated neuroendocrine tumor metastatic to regional lymph nodes, consistent with pT2 pN1, Stage IIIB cancer. NF1 patients with multiple GI tumors are at an increased risk for malignancy. Therefore, a high index of suspicion for malignancy in any patient with NF1 presenting with gastrointestinal symptoms has implications for a surgeon, warranting not only a further diagnostic investigation, but also an appropriate surgical intervention and sampling for nodal spread. Because of the possibility of a simultaneous cancer, it is crucial to assess all suspicious tumors even if the masses appear endoscopically benign.