A man in his 50s presented with a 5-year history of a left jaw mass discovered incidentally on a computed tomographic (CT) image. Fine-needle aspiration was interpreted as a “well-differentiated squamous cyst.” Routine laboratory test results and hematologic markers were normal. Examination revealed a 5-cm, minimally tender mass deep to the left parotid gland. Cranial nerve examination findings were normal, and no overlying skin or mucosal changes were noted. CT imaging (Figure, A and B) revealed a well-defined hypodense mass within the left masticator space measuring 5.0 × 3.5 cm, resulting in smooth remodeling of the left mandibular ramus. The second left mandibular molar appeared to be missing. On magnetic resonance imaging (MRI), the lesion was T2 hyperintense, mildly T1 hyperintense, without enhancement, with remodeling of left mandibular alveolar ridge. No definite site of mandibular or maxillary attachment was noted (Figure, C and D). He underwent resection via a combined transoral and transantral (Caldwell-Luc) approach. The mass was noted to be associated with an empty socket of the second mandibular molar, was not well circumscribed, and was notably adherent to some surrounding tissues, requiring meticulous dissection from the inferior alveolar nerve, temporomandibular joint capsule, and skull base. Pathologic assessment demonstrated a squamous lined cyst with parakeratosis.
Dougherty W, Jameson MJ, Mukerjee S. Incidental Large Left Masticator Space Mass. JAMA Otolaryngol Head Neck Surg. 2016;142(9):915-916. doi:10.1001/jamaoto.2016.0092