Purpose: To describe a series of anastomosing hemangiomas and report its locations, imaging features, and the use of image-guided percutaneous biopsy to establish the diagnosis.

Methods: In this institutional review board-approved, HIPAA compliant, retrospective study, an electronic pathology database was searched for all cases of anastomosing hemangioma from January 2009 to January 2015, yielding 32 cases (18 men, mean age 62 years). Tumor locations were recorded, and in a subgroup of patients with imaging, image characteristics (contour, attenuation, enhancement after intravenous contrast injection, the presence of hemorrhage or fat attenuation, and non-enhancing component) were evaluated. The number of cases diagnosed using percutaneous biopsy specimen was determined, and in a subgroup of these patients, biopsy technique and complications were assessed.

Results: Anastomosing hemangioma occurred in different locations, more commonly in the retroperitoneum (15/32, 47%), including the kidney (7/32, 22%), and more rarely in the ovary (4/32, 13%) and liver (2/32, 6%). Of the 5 cases with imaging available, four anastomosing hemangiomas were in the retroperitoneum (one in retroperitoneal fat, one para-aortic, one renal and one adrenal) and the fifth was mesenteric. Most tumors were well circumscribed (4/5, 80%), and on non-contrast CT, they appeared as mildly hyperdense (4/5, 80%) with avid contrast enhancement and heterogeneous attenuation (4/5, 80%) due to the presence of fat (2/5, 40%) or non-enhancing components (2/5, 40%). Diagnosis was rendered solely based on percutaneous biopsy in 7/32 (22%), all of which were core biopsy specimens. Fine-needle aspiration biopsy was performed in 1 case, which was non-diagnostic.

Conclusions: Anastomosing hemangioma, a rare benign vascular tumor, is most commonly seen in the retroperitoneal fat and kidneys. On imaging, they are usually circumscribed, hyperdense, and heterogeneous due to fatty or non-enhancing hypodense areas and show avid post-contrast enhancement. Percutaneous biopsy can yield the diagnosis, potentially avoiding surgery.