Duodenal pseudolipomatosis. Literature review and case report of a very unusual finding.

Pseudolipomatosis (PL) is a rare, benign, iatrogenic condition first described in colorectal mucosa. This condition is thought to arise from gas penetration into the mucosa due to mechanical or chemical injury during endoscopy. Despite these associations and its characteristic appearence, the definitive pathogenesis remains unclear and it continues to be underrecognized by some pathologists and endoscopists, which is crucial to avoid any further unnecessary treatments. Immunohistochemistry techniques play a role in differentiating PL from similar conditions such as cystic intestinal pneumatosis, intestinal lipomatosis, or lymphangiectasia. A 70-year-old man with a family history of colon adenocarcinoma was diagnosed with duodenal pseudolipomatosis after a routine endoscopic assessment. To the best of our knowledge, there have been only two reports of PL diagnosed in the duodenum. A review of over 500 duodenal biopsies at our centre revealed that no other instances were identified, emphasizing the unusual occurrence of this particular location.