Iatrogenic Sigma Perforation in a Patient with Localized Rectal and Sigma AL Amyloidosis: A Forensic Case and a Literature Review

Amyloidosis is defined as a rare group of 30 protein-folding diseases characterized by the extracellular deposition of a specific soluble precursor protein that aggregates in the form of insoluble f ibrils. The gastrointestinal tract (GI) is a common site for amyloid deposits: Among patients with systemic amyloidosis, at least 70% present with gastrointestinal deposition. Rarely, the deposition is exclusively localized in this area, leading to various gastrointestinal symptoms (bleeding, weight loss, etc.). In this case report, we present a rare and unusual form of localized gastrointestinal amyloidosis, diagnosed after a post-mortem examination of an 83-year-old woman who died due to septic shock resulting from post-colonoscopy iatrogenic perforation of the sigma, in a suspected medical liability case. Morphological examination revealed AL amyloid deposits within the muscular wall of the submucosal vessels of the rectum, which caused increased friability of the vessels and ischemic changes in the intestinal mucosa. A renal cell carcinoma (RCC) was found, which might be related to amyloid deposits, as reported by the literature. Amyloid deposits are an unknown and unpredictable pathological substrate that increase the risk of iatrogenic perforation. Analysis of the medical documentation did not reveal any censurable conduct in terms of prescribing the procedure, technical execution, or subsequent management of the patient following the perforation. GI amyloidosis should be part of the risk stratification of patients with rectal bleeding and gastrointestinal symptoms, and awareness is essential to guide subsequent diagnostic and therapeutic approaches and investigate underlying causes.