Peritoneal hematoma refers to hemorrhage occurring in the retroperitoneal space, which is a frequently encountered complication of abdominal and lumbar injuries. The primary etiologies include pelvic and lumbar vertebral fractures, followed by rupture of retroperitoneal organs such as the duodenum, pancreas, kidney, and bladder. Moreover, it can also be attributed to ruptured major blood vessels within the retroperitoneum resulting in bleeding.

Intercostal artery injury is predominantly caused by trauma [1], with blunt trauma resulting in rib fractures often accompanied by hemothorax, pneumothorax, pulmonary contusion, or less frequently, hematoma in the chest and abdominal wall [2]. To our knowledge, there have been no reports documenting massive retroperitoneal hematoma caused by intercostal artery bleeding following blunt abdominal trauma. In this particular case study, a patient presented with a substantial retroperitoneal hematoma subsequent to blunt abdominal trauma. Abdominal ultrasound and CT scans did not reveal any injuries to the abdominal organs or major blood vessels. However, angiography showed extravasation from a branch of the twelfth intercostal artery, implicating it as the source of hemorrhage. Following embolization of this specific artery, bleeding ceased and gradual improvement was observed in the patient’s condition.

In the majority of cases, symptoms resembling those of other common abdominal conditions are often observed in retroperitoneal hematoma, leading to frequent instances of underdiagnosis and neglect. This can subsequently result in severe complications and even mortality. Abdominal pain is the most prevalent presenting symptom, followed by a reduction in hemoglobin levels. Therefore, any unexplained decline in hemoglobin should raise suspicion regarding the possibility of a retroperitoneal hematoma [3]. Furthermore, certain subtle indications such as Grey Turner’s sign and Cullen’s sign may also serve as diagnostic clues for a retroperitoneal hematoma [4].

The diagnosis of retroperitoneal hematoma primarily relies on enhanced CT scanning, which serves to identify the presence and precise location of the hematoma while also providing guidance for treatment [5]. Notably, the detection of high-density shadows within the hematoma indicates extravasation of contrast agent, thereby suggesting active bleeding.

Studies have demonstrated that among patients with retroperitoneal hematoma, 50% may experience hemodynamic instability, only 17.9% necessitate vasopressor support. In the majority of cases, medical management serves as the primary treatment modality, with a minority requiring surgical intervention or endovascular embolization [3]. Transcatheter arterial embolization is considered a reliable and feasible therapeutic approach for controlling intercostal artery bleeding instead of thoracotomy [6]. Nevertheless, this technique’s efficacy varies due to its operator-dependency and carries a potential risk of postoperative pseudoaneurysm formation [7].

In conclusion, the occurrence of massive retroperitoneal hematoma caused by intercostal artery is an exceedingly rare and life-threatening condition. For patients presenting with hemodynamic instability, transcatheter arterial embolization is recommended as the primary treatment modality.