Malignant fibrous histiocytoma of the floor of mouth: a case report and review of the literature.

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma in late adulthood and usually occurs in the limbs, trunk, and peritoneum. Less than 10% of MFH cases occur in the head and neck region. The clinical manifestations and pathological features of MFH are atypical, and it is difficult to make a clinical diagnosis. We describe a rare case of MFH of the floor of mouth and provide our diagnosis and treatment experiences. Through this review, we also evaluate the origin, World Health Organization (WHO) classification, clinical presentations, pathological features, treatment methods, and prognosis of MFH. MFH may originate from fibroblasts or primitive mesenchymal cells. MFH was defined as undifferentiated pleomorphic sarcoma in the 2002 WHO classification of bone and soft tissue tumors. The most common manifestation of MFH is a painless enlarging nodule, often without overlying epidermal ulcers. Jaw lesions are usually found after displays of swelling, pain, paresthesia, and loose teeth. MFH is composed of pleomorphic spindle cells, usually with hemorrhage, necrosis, and lymphocyte infiltration. The main treatment method is surgical resection. Moreover, radiotherapy and chemotherapy have certain auxiliary effects. The local recurrence and distant metastasis of MFH are common, and the prognosis is poor. Therefore, determining the histopathological features of MFH and conducting appropriate immunohistochemical examinations are crucial in establishing the correct diagnosis. In-depth study is required in order to have a better understanding of head and neck MFH.