Periosteal desmoid tumour: a rare finding in the oral cavity

Summary

A 55-year-old female patient reported with an intraoral well-localised asymptomatic swelling on the right side of the mandible in relation to the right mandibular first molar along with a history of trauma 6_months back. The microscopic examination revealed a well-circumscribed lesion consisting of spindle cells arranged in storiform pattern associated with the buccal cortical plate. Immunohistochemistry (IHC) revealed faint nuclear positivity for beta-catenin. The above findings led to our diagnosis of periosteal desmoid, which is rarely reported in the head-and-neck region. The major challenge in the diagnosis of such lesions is good clinicopathological correlation as the differential diagnosis of spindle-cell lesions is vast and needs IHC confirmation.