Rationale: Primary epiploic appendagitis (PEA) is a rare cause of acute abdomen caused by spontaneous torsion or venous thrombosis of epiploic appendices, it commonly manifests with acute lower quadrant pain, thus may mimic acute diverticulitis, appendicitis, or mesenteric infarction. Patient concerns: In this case report, we report a 44 years old man who presented with persistent sharp pain in the left lower quadrant abdomen, Laboratory tests were mostly normal, contrast enhanced computed tomography (CECT) revealed a slightly high density shadow with fat foci in the middle was presented around the local descending colon, accompanied by the adjacent peritoneal thickening. Diagnoses: He was diagnosed with PEA as confirmed by an abdominal contrast enhanced computed tomography (CECT) scan. Interventions: He was followed up in the clinic without any dietary restrictions, antibiotic or analgesic drugs use. Outcomes: The abdominal pain gradually subsided a week later, and there were no recurrence of the symptoms during follow-up. Lessons: In our case, the diagnosis of PEA using CECT allows the patient to avoid surgery and other invasive treatment.