Hemangiomas are very common benign soft-tissue tumors. However, fewer than 1% are intramuscular,1and only 14% to 21% of all intramuscular hemangiomas (IHs) are found in the head and neck.2Evidence suggests that IHs are congenital in origin.3Intramuscular hemangiomas can be subtyped based on the caliber size of the vessels. Capillary small-vessel–subtype hemangiomas have vessels that are smaller than 140 μm in diameter. Large-vessel or cavernous-type hemangiomas have vessels that are larger than 140 μm in diameter. The mixed type contains both large and small vessels. Immunohistochemical staining of endothelial cells of hemangiomas is positive for CD31.
Radiology Quiz Case 2: Diagnosis. Arch Otolaryngol Head Neck Surg. 2010;136(1):98. doi:10.1001/archoto.2009.183-b