Non-traumatic Internal Oblique Muscle Hematoma

A 69-year-old obese man (body mass index, 30.3) presented with acute left abdominal pain after severe coughing. He had no history of direct abdominal trauma. He was not receiving anticoagulant therapy. A physical examination showed a smooth painful mass on his left abdominal wall. The laboratory findings were a platelet count of 196,000/ mm and a normal range of coagulability. Ultrasonography revealed a hypoechoic mass in the left lateral abdominal wall (Picture 1a). Unenhanced computed tomography showed a distensible high-density mass consisting of fluidfluid levels in the left internal oblique muscle (Picture 1b and c), and the transverse abdominal muscle was intact. Extravasation could not be evaluated because of his renal dysfunction. He was diagnosed with internal oblique muscle hematoma and was conservatively treated. Ecchymosis presented three days later on his left lateral abdomen (Picture 2). Spontaneous abdominal wall hematoma is considered to occur as a non-traumatic injury to vessels or muscles of the abdominal wall and has several risk factors, including overcontraction due to coughing or vomiting and weakness of the vessel wall as a result of hypertension, arteriosclerosis, obesity or pregnancy (1, 2). In spontaneous ab-