Chronic expanding hematoma in the retroperitoneal space: a case report

Abstract

Background: Chronic expanding hematoma is a rare condition that develops after surgery, trauma, or injury. It can also develop at any location in the body in the absence of trauma. Clinical findings and various diagnostic imaging modalities can aid in the differential diagnosis of this condition. In general, hematomas are naturally reabsorbed and rarely cause serious problems. However, hematomas that develop slowly without a history of trauma, surgery, or bleeding disorders could be difficult to differentiate from soft tissue neoplasms. In the present case, we describe a patient, without any history or physical evidence of trauma, who exhibited a large chronic expanding hematoma in the retroperitoneal space that resulted in hydronephrosis because of the pressure exerted on the left ureter.

Case presentation: A 69-year-old man presented to our hospital with a swollen lesion in the left flank. A mass, 19 cm in diameter, was detected in the retroperitoneal space by computed tomography. We suspected the presence of a chronic expanding hematoma, soft tissue tumor, or left renal artery aneurysm. Surgical treatment was performed. However, postoperative histopathological examination indicated that the mass was a nonmalignant chronic expanding hematoma. No recurrence was observed during a 2-year follow-up period.

Conclusion: In patients without a history of trauma who present slowly growing masses, the differential diagnosis should include chronic expanding hematoma in addition to cysts and soft tissue tumors. Moreover, the use of magnetic resonance imaging and computed tomography is essential to differentiate between chronic expanding hematoma and soft tissue tumors.

Figure 1

Enhanced abdominal computed tomography. (a) Axial view: The retroperitoneal mass is 20 cm × 15 cm × 13 cm in size and well-circumscribed. (b) Sagital view: The left kidney is compressed upward, and hydronephrosis is evident.

Figure 2

Abdominal magnetic resonance imaging (MRI). The T1-weighted images show high signal intensity and many partition walls.

Figure 3

Abdominal MRI. The T2-weighted images show high signal intensity in a major portion of the mass. Heterogeneous signal intensity with hyperintense and hypointense areas is also observed.

Figure 4

Gross lesion with a hard connective tissue capsule.

Figure 5

An old clot and friable material that was contained within the hematoma.

Figure 6

Microscopic examination indicating the presence of fibroblastic granulation tissue and degenerative erythrocytes within the hematoma, which are surrounded by thick collagenous fibrous tissue.