OBJECTIVETo investigate the clinicopathologic features and differential diagnoses of non-involuting congenital hemangioma (NICH) in children.

METHODSThe clinical, morphologic and immunophenotypic characteristics of 22 cases of NICH were retrospectively analyzed.

RESULTSThe mean patients' age at diagnosis was 4.2 years, with a male to female ratio of 1.75:1. The tumors were located in the head and face (5 cases), neck (3 cases), body (6 cases), upper limbs (5 cases), and lower limbs (3 cases). Histologically, the tumor was dominated by rather large lobules of small vessels that were mostly rounded, curved, small and thin-walled, and were lined by endothelial cells surrounded by one or more layers of pericytes. The center of the lobules was occupied by one or more thin or thick walled vessels, which were surrounded by fibrous and fatty tissue, which contained abnormal arterial and venous structures. At the edge of the lobules there were lymphatic vessels. Immunohsitochemical study showed that tumor cells in NICH were positive for CD34 (22/22), CD31 (22/22), SMA (22/22), vimentin (22/22) and Glut1 (0/22). D2-40 expression was located at the edge of the capillary lobules.

CONCLUSIONSNICH is a benign lesion. Clinically and pathologically, it needs to be differentiated from rapidly involuting congenital hemangioma, infantile hemangiomas, tufted angioma, vascular malformation, and others.