Case ReportFatal Retroperitoneal Bleeding in Neurofibromatosis Type 1 A Clinically Occult ComplicationVoudouri, Mariana MD∗; Chambers, Meagan MD, MS, MSc†; Baker, Michael L. MD∗,‡; Kerr, Darcy A. MD∗,‡ Author Information From the ∗Department of Pathology and Laboratory Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH †Department of Pathology and Laboratory Medicine, University of Washington, Seattle, WA ‡Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH. Manuscript received August 16, 2022; accepted October 22, 2022. The authors declare no conflict of interest. Reprints: Darcy A. Kerr, MD, Department of Pathology and Laboratory Medicine, Dartmouth-Hitchcock Medical Center, One Medical Center Dr, Lebanon, NH 03756. E-mail: [email protected]. The American Journal of Forensic Medicine and Pathology: November 18, 2022 - Volume - Issue - 10.1097/PAF.0000000000000806 doi: 10.1097/PAF.0000000000000806 Buy PAP Metrics Abstract Neurofibromatosis type 1 (NF1) is a common, autosomal dominant neurocutaneous syndrome. The most frequent clinical manifestations include multiple neurofibromas, café-au-lait spots, dystrophic scoliosis, benign and malignant peripheral nerve sheath tumors, and paragangliomas. Neurofibromatosis type 1 vasculopathy is a less well-recognized constellation of vascular pathologies that can cause significant medical complications in patients with NF1. A rare manifestation of this process is neurofibroma infiltration of vasculature with resultant bleeding. The case presented herein illustrates a rare example of a massive fatal hemorrhage due to disruption of a large paraspinal artery in the setting of a diffuse, infiltrative neurofibroma. This case highlights the potential of benign neurofibromas to infiltrate major blood vessels, leading to extensive bleeding and death. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.