Mandibular central leiomyosarcoma with high telomerase activity: a case report.

: Leiomyosarcoma is a malignant lesion of smooth muscle origin, and rare in the oral region. This report presents an extremely rare case of intraosseous leiomyosarcoma of the mandible. After visiting other general hospital, a 29-year-old man was referred to our hospital because of a pain in the left mandibular region with paresthesia of the left mental region. The left mandibular third molar had already been extracted in another hospital, and a brownish mass occupied the corresponding region. A panoramic radiograph showed osteolytic destruction around the left mandibular angle and ramus. A computed tomography scan and magnetic resonance image revealed perforation of the lingual and buccal cortex of the mandible. A non-epithelial malignant tumor was diagnosed from a biopsy specimen. Immediately, we resected the tumor and reconstructed the titan plate under general anesthesia. A final diagnosis of leiomyosarcoma was made from a surgical specimen based on findings showing a proliferation of hyperchromatic spindle cells, which were positive for the markers α- smooth muscle actin, calponin, HHF35, and desmin. The S-100, epithelial membrane antigen, and cytokeratin markers were negative. The patient had 3 courses of adjuvant chemotherapy after the operation, and showed no evidence of recurrence during the follow-up at the outpatient clinic. However, 2 years after the first operation, lung metastases and local recurrence were detected. Additional chemotherapy was not effective. Finally, the patient died almost 3 years after the first operation.