Abdominal Cocoon Syndrome With Greater Omental Hypoplasia: A Rare Anatomical Insight and Diagnostic Challenge.

Abdominal cocoon syndrome, or idiopathic sclerosing encapsulating peritonitis (SEP), is an uncommon cause of small bowel obstruction marked by the encasement of bowel loops within a dense fibrocollagenous membrane. Due to its rarity and nonspecific presentation, diagnosis is frequently delayed, particularly in patients without prior abdominal surgery or known risk factors. We report a diagnostically challenging case of a 53-year-old male with an 18-month history of recurrent gastrointestinal obstruction, including bilious vomiting, oral intolerance, and epigastric pain. Multiple prior evaluations yielded inconclusive findings. Contrast-enhanced computed tomography raised suspicion for SEP, prompting exploratory laparotomy. Intraoperative findings confirmed SEP, along with a rare anatomical anomaly-hypoplasia of the greater omentum. Surgical excision of the encasing membrane and adhesiolysis resulted in complete symptom resolution, with no recurrence at six-month follow-up. This case underscores the importance of clinical vigilance in recognizing abdominal cocoon syndrome and highlights the first reported co-occurrence of SEP with greater omental hypoplasia. Surgical exploration not only confirmed the diagnosis but also achieved full recovery. The embryologic implications of omental hypoplasia may offer new insights into SEP pathophysiology and merit further investigation.