Intramuscular hemangioma of the head and neck.

Intramuscular hemangiomas (IMH) are uncommon tumors in the head and neck region, occurring most often in the trunk and extremities. Preoperative misdiagnosis is common because of the deep location of these tumors. Ten recent cases of head and neck IMH are presented, five of which involve the masseter muscle--the most frequent site of involvement in the head and neck. Masseter IMH occurred almost exclusively in the pediatric age group. The clinical presentation, radiographic and histologic findings, treatment, complications, and outcome of these patients are presented. The vital role of preoperative diagnosis using magnetic resonance imaging (MRI) is discussed, as well as a review of the natural history of IMH and indications for surgical intervention.