An oblique muscle hematoma as a rare cause of severe abdominal pain: a case report

A 42-year-old Japanese man presented with a painful, enlarging, lateral abdominal wall mass, which appeared after playing baseball. Abdominal computed tomography and ultrasonography showed a large soft tissue mass located in the patient’s left internal oblique muscle. A diagnosis of a lateral oblique muscle hematoma was made and the patient was treated conservatively.Physicians should consider an oblique muscle hematoma during the initial differential diagnosis of pain in the lateral abdominal wall even in the absence of anticoagulant therapy or trauma.Abdominal wall hematomas are an uncommon cause of acute abdominal pain and are often misdiagnosed. They result from rupture of the epigastric vessels or the deep circumflex iliac artery (rarely), or from tears of the fibers of the rectus abdominis or lateral oblique muscles [1,2]. They may occur because of trauma, physical exercise, recent surgery, or injection procedures. They may also occur because of increased intraabdominal pressure from coughing, sneezing, vomiting, or straining during urination, defecation, and labor [1,3-6]. Other predisposing factors include increased age, arterial hypertension, atherosclerosis, and systemic anticoagulant therapy. Most abdominal wall hematomas occur in the rectus sheath, and a hematoma within the oblique muscle is very rare. Here we report a case of an oblique muscle hematoma in a middle-aged patient.A 42-year-old man presented with a painful, enlarging, lateral abdominal wall mass, which appeared after playing baseball. He gave no history of direct abdominal trauma such as collision with another player. He had a history of hyperuricemia; however, he had not undergone any therapy for the same. There was no family history of bleeding diathesis or hematological diseases. On physical examination, his vital signs were as follows: temperature 36.8°C, blood pressure 108/69 mm Hg, pulse rate 58 beats/min, and respiratory rate 12 breaths/min. A firm mass was palpable over the left lat