Peritoneal amyloidosis: unusual localization of gastrointestinal amyloidosis

Amyloidosis is a rare disease that results from the extracellular deposition of amorphous fibrillar protein. It is usually observed in a systemic form. Gastrointestinal involvement is frequent but peritoneal localization is unusual. A 43-year-old male was investigated for nephritic colic. Morphologic explorations revealed small intestine agglomerans in the periumbilical region, infiltration of peritoneal fat and multiple coelio-mesenteric lymph nodes. There were no clinical or biological abnormalities and endoscopic examinations were normal. The patient then underwent an exploratory laparoscopy. Macroscopically false membranes were seen throughout the peritoneum and small bowel without ascites. Anatomopathologic examination diagnosed peritoneal amyloidosis. After several investigations a diagnosis of a primary peritoneal amyloidosis was confirmed. The patient was treated with melphalan and prednisone with a favorable outcome. Our case illustrates a particular presentation of peritoneal amyloidosis. Despite improved imaging methods, peritoneal biopsy remains essential for diagnosis.