Spontaneous rectus sheath hematomas: clinical and radiological features.

We reviewed the clinical and radiological features in eight patients with spontaneous rectus sheath hematoma (RSH). The diagnosis was confirmed at surgery in four patients, and spontaneous resolution occurred in the other four. All patients were elderly adults. Acute abdominal pain and a palpable mass after muscular strain, such as coughing or twisting, were features highly suggestive of RSH. Sonographically, these hematomas may be confused with abdominal wall tumors. On CT scans, a hyperdense mass posterior to the rectus abdominis muscle with ipsilateral anterolateral muscular enlargement is considered characteristic of acute RSH, although chronic RSH may be isodense or hypodense relative to the surrounding muscle. MRI is very useful in the diagnosis of RSH, which is demonstrated as a high signal intensity area on both T1- and T2-weighted images, especially when the CT findings are not specific for RSH.