Intramuscular lipoma. A differential diagnosis of great prognostic relevance

: Lipomata of the head and neck mostly present as cosmetically disturbing, superficial lesions lying within the subcutaneous tissue such that they can be easily removed by minor surgical interventions. In cases of deeply extended, lipomatous tumors, as reported here regarding two exemplary cases, physicians should always take into account that they might have to deal with infiltrative, intramuscular lipomata or even malignant neoplasms, especially if concomitant functional disorders are observed. Even though such tumors are rare in the head and the neck, preoperative planning must anticipate these possible pathological entities. At any stage, modification of the surgical procedure should be possible according to the intraoperative findings, as these tumors are prone to recurrence after incomplete resection. The actual diagnosis with infiltration of the surrounding tissue cannot be sufficiently made either by adequate imaging techniques or by preoperative fine-needle cytology but only by histological workup of the resected, tumorous tissue.