Diabetic Myonecrosis of Isolated Internal Oblique Muscle, a Rare Presentation of an Uncommon Condition: A Case Report

Introduction Diabetic myonecrosis is usually encountered in patients with long-standing diabetes mellitus, particularly those with uncontrolled glycemia and target organ damage. It is considered a form of microangiopathy and commonly involves large muscles of the lower extremities. Upper limb muscles are involved infrequently, and involvement of trunk muscles is extremely rare. Isolated involvement of abdominal muscle has never been reported so far. Case report A 50-year-old gentleman with fifteen-year history of type 2 diabetes mellitus presented with pain and swelling of left lumbar region for the preceding two weeks. He had been treated with oral anti-diabetic agents with very poor glycaemic control (recent glycated haemoglobin: 10.4%). Abdominal examination revealed a firm, tender ill-defined non-ballotable mass without local warmth, which did not disappear on right lateral decubitus. Computed tomography (CT) documented enlarged left internal oblique muscle with relatively low attenuation (right: 45 HU, left: 26 HU) on unenhanced scan. The corresponding area was iso to hypointense and heterogeneously hyperintense on T1 and T2 weighted magnetic resonance imaging (MRI), respectively. Based on typical clinical and radiological appearances, a diagnosis of Diabetic myonecrosis was made and the patient responded to conservative management. Important differential diagnoses that should be considered in patients with similar presentation are local infection, truncal radiculoneuropathy and lumbar hernia. MRI with/without CT scan is needed to reach a definite diagnosis.