A spontaneous abdominal wall hematoma developed in a 70-year-old woman with interstitial lung and mixed connective tissue disease during hospitalization for dyspnea. Diagnosed with a recurrent deep venous thrombosis of her left common femoral vein, enoxaparin by abdominal subcutaneous route and warfarin were administered. Within 48 hours, the patient developed pain, tenderness, and a large area of bruising in the left lower quadrant. Figure 1 Computed tomography (CT) scan sagittal section demonstrating a 12.8 × 5.3 × 11.4 cm abdominal wall hematoma in left lower quadrant with a fluid-fluid level, representing layering blood products. Figure 2 Cross-section CT image through the abdominal wall hematoma. Figure 3 After cannulation of right femoral artery, angiography of inferior epigastric and lateral circumflex arteries was obtained. Several blushes representing active bleeding from lateral circumflex artery were identified (see arrow). Figure 4 Successful coil embolization of the lateral circumflex artery is demonstrated (see arrow). Abdominal wall hematoma is uncommon, but may be a life-threatening condition. Risk factors include older age, female sex, systemic anticoagulation, abdominal wall trauma, pregnancy, and impaired renal function.1 Clinical manifestations include abdominal pain, abdominal wall ecchymosis, drop in hematocrit, and a positive Carnett's sign (increase in abdominal pain when a supine patient tenses his or her abdominal wall by lifting their head and shoulders off the exam table, indicating the abdominal wall and not the abdominal cavity as the source of pain).2 In severe cases, signs of hemodynamic compromise can occur, as developed in our patient. Treatment in cases of hemodynamic compromise includes resuscitation with intravenous fluids and blood products, and normalization of coagulation status with the fresh frozen plasma and vitamin K. Surgical management (which is extremely challenging) or embolization by angiographic specialists is necessary in patients who fail conservative measures.