Idiopathic encapsulating peritoneal sclerosis presenting with abdominal mass.

A man in his late 30s presented with a history of recurrent colicky abdominal pain, bilious vomiting and intermittent mass formation in the lower abdomen. The mass was mobile, non-tender and fluctuant, and appeared in the right iliac fossa during episodes of pain and disappeared once the pain subsided. Contrast-enhanced CT (CECT) scan revealed a thick membrane-like structure covering the clumped small bowel loops, suggestive of an abdominal cocoon. A midline laparotomy was carried out with extensive adhesiolysis, and a membrane incision was performed. The final histopathological diagnosis was primary encapsulating peritoneal sclerosis. Encapsulating peritoneal sclerosis of idiopathic origin is rare and typically presents as an acute or subacute intestinal obstruction. A CECT scan is the diagnostic modality of choice, with a thick peritoneal membrane covering the small bowel loops being the hallmark sign. Surgical intervention is the preferred treatment for idiopathic cases, while medical management may address secondary causes.