Clinical and histopathological observations and biochemical analysis of mandibular malignant fibrous histiocytoma

Malignant fibrous histiocytoma of the oral region is rare. Clinical course, histopathological observations and biochemical analysis of malignant fibrous histiocytoma of the mandible in an 18-year-old male is reported.The clinical findings revealed rapid enlargement of two nodular tumors 5 cm and 3cm diameter, in the molar region of the right mandible and tender regional lymph nodes. Radiographically, separation of the wisdom tooth and the second molar tooth and an irregular radiolucent area reaching to the mandibular canal were shown. Segmentary resection of the mandible and radical neck dissection were carried out. Postoperative course of the patient was uneventful and no recurrence or metastasis was found after 2 years.Histopathologically, most of the tumor consisted of a highly myxoid tissue. In the myxoid area widely spaced spindle cells, pleomorphic cells and giant cells were arranged in a matrix.In electron microscopic examination, fibroblast-like cells, histiocyte-like cells and polynuclear giant cells were observed.By the biochemical methods, type I, III and V collagen were detected by the SDS-PAGE method. Dihydroxylysinonorleucine was found to be the major reducible cross-link in this collagen and its ratio to hydroxylysinonorleucine is 2.4. This suggested that the collagen is similar to the hard tissue collagen or at the young and growing stage. Pyridinoline and histidinoalanine were found to be the noreducible cross-link in this collagen.