Core biopsy as a simple and effective diagnostic tool in head and neck focal myositis.

Most unilateral head and neck masses are benign, although malignancy is a possibility in some cases. However, there are other rare causes of unilateral neck masses, such as focal myositis, which is a rare, benign condition belonging to the family of inflammatory pseudotumors of the skeletal muscles, with rare presentations in the head and neck region. Focal myositis presents as a rapidly enlarging neck mass that can be misdiagnosed by fine-needle aspiration biopsy and/or radiologic imaging as either an infective or a neoplastic process.