A retroperitoneal hematoma, developing primarily after abdominal or pelvic blunt trauma, is a potentially life-threatening complication of various malignancies that presents with non-specific symptoms such as pain in the abdomen, the back, the leg, and the hip area, as well as abdominal distension and ascites. The diagnosis must be made early on, and imaging studies, including ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) should be used to determine the exact location of metastatic spread.
Retroperitoneal hematoma (RH) can appear as a result of various etiologies, including the chronic use of anticoagulants (warfarin, heparin, antiplatelet drugs), surgical procedures, rupture of aortic aneurysms, and blood dyscrasias, but by far, the most common cause is abdominal or pelvic trauma     . Hence, the terms spontaneous, traumatic, and idiopathic retroperitoneal hematomas are used in the literature   . Mortality rates for traumatic RH range from 6-60% according to different reports, suggesting that an early diagnosis is of critical importance  . Unfortunately, this condition is missed up to 10% of patients . The clinical presentation, however, might not always be indicative of a RH, with most common signs being abdominal pain and a sense of suprainguinal tenderness, but pain may sometimes appear in the leg, the hip, or radiate to the back   . Femoral numbness and neuropathy were identified in up to a third of cases  . RH can also present as an abdominal mass accompanied by distension, whereas newly form ascites is a highly indicative sign of an ongoing process in the abdomen   . In severe cases, patients suffer from life-threatening hypotension and a severe hematocrit drop that is unresponsive to standard therapy .
The diagnosis can be missed because of the nonspecific presentation of retroperitoneal hematoma , which is why a thorough examination of patients who suffered from recent abdominal or pelvic trauma, or who are receiving anticoagulant therapy, must be carried out when the previously mentioned complaints are noticed. For this reason, a detailed patient history that confirms the use of medications or recent trauma may be the crucial step in making a presumptive diagnosis. After a comprehensive physical examination, imaging studies need to be employed. Abdominal ultrasonography, although being a fast and convenient first-line study, has a very low detection rate of retroperitoneal hematomas, making CT scan the gold-standard for identifying this clinical entity . Acute and subacute hematomas (being present for < 7 days or between 7 days and 7 weeks, respectively) have a high-attenuating heterogeneous appearance on CT, whereas chronic hematomas (lasting > 7 weeks), exhibit a low-attenuating pattern due to degradation of red blood cells and subsequent accumulation of hemosiderin  . Some reports have observed the striking similarities of RH with malignant tumors (eg. sarcomas), but the typical findings of hematomas - a sharply defined margin and progressive reduction in size are used to discriminate between these lesions   . MRI requires more preparation and time that may not always be feasible, but its superiority compared to CT by revealing a hyperintense mass on both T1 and T2-weighted images is well-documented  .