Multislice computed tomography evaluation of primary abdominal fat necrosis: a rare cause of acute abdominal pain

Purpose
Abdominal fat necrosis is a rare cause of abdominal acute pain, classified into primary or secondary according to the cause. Primary fat necrosis includes epiploic appendagitis or idiopathic infarction of the greater omentum. This retrospective study focuses on multislice computed tomography (MSCT) findings and diagnosis of primary abdominal fat necrosis as a cause of acute abdomen.

Material and methods
This was a retrospective study with 20 patients included, presented to emergency room with acute abdominal pain diagnosed as primary fat necrosis. Retrospective evaluation was made of the patients’ clinical data, presentation, CT studies done at the acute stage, and their primary and final diagnosis.

Results
Twenty patients (eight male and 12 female, mean age 45 years, age range 20-70 years) diagnosed with abdominal fat necrosis (primary omental infarct) on CT imaging between October 2014 and June 2018 were evaluated. Clinically, five patients were suspected to be cholecystitis¸ eight patients as appendicitis, and four patients as diverticulitis. In addition, three patients had renal colic and were suspected to have ureteric stones; they showed suspected areas of abnormal fat density in non-contrast CT of the urinary tract. Idiopathic omental infarctions were detected in 13 patients on CT; all were on the right side. Laparoscopic excision was done for all. The other seven patients had epiploic appendagitis, seen on the left side, treated with conservative management.

Conclusions
Primary fat necrosis, although rare, can be presented as acute abdomen. MSCT is the main diagnostic tool for diagnosis of omental infraction and differentiation between other causes of acute abdomen.