Intramuscular lipoma of the sternocleidomastoid muscle.

Intramuscular lipoma is a rare benign mesenchymal tumor that infiltrates the skeletal muscle. These lipomas are usually found on the extremity, but rarely occur in the head and neck. To our knowledge, only 4 cases of intramuscular lipoma in the sternocleidomastoid muscle have been reported in the literature. The recurrence rate of intramuscular lipoma is high, and it shows the pattern of infiltration to tissues, and thus different from general lipomas, its resection should include adjacent normal muscular tissues. In addition, although rare, concerning intramuscular lipoma that developed in the head and neck area, because important structures are present densely in a small space, it is important to establish a preoperative plan by determining the size and location of the tumor through preoperative clinical and radiologic tests. We had a case of intramuscular lipoma in sternocleidomastoid muscle and resected the mass completely including a portion of attached muscles. The postoperative course was uneventful, and no evidence of recurrence occurred after 6 months of follow-up.