Carcinoma mucoepidermoid arising as an intraoral swelling and osseous involvement: report of a case diagnosed as a cyst

A 56-year-old female presented with a 30 mm nodular lesion on the left side of the retromolar trigone. The lesion caused slight cortical displacement. The image scans demonstrated a well-defined radiolucent area with often corticated margins, preserving the mandibular canal. On CT images, the lesion eroded through the lingual cortical plate into the gingival soft tissues. The lesion was removed under general anesthesia, and the patient has been under observation for 7 months. Microscopically, solid and multicystic growth patterns were present, with mucous and epidermoid cells. Intermediate cells were also detected. The amount of cyst formation was higher than 80%, with a high proportion of mucous cells and a low rate of mitosis. Atypia was mild, but necrosis and vascular/perineural invasion were absent. Then, a diagnosis of low-grade mucoepidermoid carcinoma stage pT2, pNx was rendered. The patient is currently under periodic review and has no relapse.