Imaging of nontraumatic hemorrhagic hepatic lesions.

Spontaneous hepatic bleeding is a rare condition. In the absence of trauma or anticoagulant therapy, hepatic hemorrhage may be due to underlying liver disease. The most common causes of nontraumatic hepatic hemorrhage are hepatocellular carcinoma and hepatic adenoma. Such hemorrhage can also occur in patients with other liver tumors, such as focal nodular hyperplasia, hemangiomas, and metastases. Other conditions associated with this entity include HELLP syndrome, amyloidosis, and miscellaneous causes. Imaging plays a significant role in the diagnosis and management of this potentially lethal entity. In the appropriate clinical setting, the diagnosis of a hemorrhagic liver lesion is suggested when a hyperechoic mass or a mass with hyperechoic areas is seen at ultrasonography, a hyperattenuating mass is seen at computed tomography (CT), or a mass with high-signal-intensity areas is seen at T1-weighted magnetic resonance (MR) imaging. The signal intensity of blood can be increased or decreased on MR images depending on when the hemorrhage is imaged. The presence and extent of commonly associated subcapsular hematomas and hemoperitoneum can be easily ascertained with CT. During the first 24-72 hours, acute hematomas are hyperattenuating on nonenhanced CT scans; later, they decrease in attenuation and sometimes develop a pseudocapsule.