RESUMO
We report a case of primary low-grade leiomyosarcoma of the mandible in an otherwise healthy young woman. The neoplasm presented as a painful, pericoronal gingival swelling that mimicked an acute periodontal infection. It was managed accordingly, with curettage, debridement, and antibiotics. When the lesion failed to respond to this treatment approach, a biopsy was performed. Microscopy revealed a malignant mesenchymal neoplasm which, on immunohistochemistry analysis, demonstrated reactivity for smooth muscle actin (SMA) and vimentin. This established the diagnosis of leiomyosarcoma; subsequently, an en bloc resection of mandibular bone and overlying soft tissue was performed. Close follow-up for over 10 years has revealed no evidence of recurrent or metastatic disease. Since the patient was taking oral contraceptives prior to the onset of the lesion, a possible link between estrogen and smooth muscle tumors is considered.
