Ossifying fibro myxoid tumor (OFMT) is a rare soft tissue neoplasm and may present diagnostic difficulty. Only a few cases of oral cavity are described. A 49 –year-old male presented with a mass in the vestibular region of the mandible middle line, complaining of pain for the last three months. The mass contains spindle and polygonal mesenchymal cells on the myxoid ground in histochemical examinations. The tumor had a partial fibrous capsule surrounded by a non-metaplastic bone trabeculae. Histopathological examination was typical for OFMT. Although most cases of OFMT follow a benign course, recurrence and metastasis have been reported. Therefore, this type of tumor should be followed carefully.
OFMT is rarely observed introorally in this article.
OFMT bone resorption is rarely observed.
In the literature, both bone resorption and intraoral observation are known as only 1 case.
Ossifying fibro myxoid tumor (OFMT), first described by Enzinger et al., in 1989, is a rare mesenchymal neoplasm that typically arises in the extremities. These types of tumors often appear as a painless, well-defined subcutaneous mass usually attached to the nerve, muscle, or cartilaginous. In more than 70% of cases, extremities are involved; less frequently involved areas include the head and neck, and the mediastinum [ ]. These tumors are uncommon in the oral cavity; however, a few cases have been reported [ ]. OFMTs particularly affect adults [ ]. OFMTs are usually follow a benign course and are generally treated with complete excision [ ]. Recurrence in the head and neck area is reported 21% of the time and metastases are quite rare [ , ]. OFMTs are rare soft tissue neoplasms of uncertain etiology, characterized by the proliferation of round to spindle-shaped cells arranged in cords and embedded in a fibro myxoid matrix [ ]. OFMTs are multilobular and appear to be an incomplete metaplastic bone shell [ , ]. After the characterization of this tumor by Enzinger et al., about 220 cases have been published, mostly seen in the extremities and found in subcutaneous tissues [ , ]. The trunk, retroperitoneum, mediastinum, and to a lesser extent, the head and neck region may also be affected. It is very rare to see OFMTs only in the oral cavity [ ]. Most cases of OFMT exhibit a mostly symptom-free biological behavior. Local recurrence, which is treated with local curettage, has been reported at a rate of 20–27%. In rare cases, it may show an aggressive biological behavior. The presence of these cases has been associated with the development of metastasis [ , ].
The present article reports an OFMT case in the intraoral region of a 49-year-old male patient and includes the histogenesis, histopathological features, biological behavior, and surgical treatment management of the OFMT.
A 49- year-old male was admitted to Ataturk University, Faculty of Dentistry, Department of Oral Surgery with a swelling complaint in the vestibular region of the mandible middle line for the last 3 months. Prior to presentation, he mentioned that he had visited three doctors and had received antibiotic treatment for the affected area. There was no systemic disease in his medical history. Intraoral examination showed a mass of 3x2x2cm located in the vestibulum of the mandibular middle line. The firm mass was not ulcerated. The patient’s first molar teeth are missing in all four quadrants. The lower left second molar showed non-vital in a vitality test. The orthopantomographic showed an irregular mass with an incomplete ring of peripheral calcification. A few sclerotic foci were also observed. It was decided to proceed with an aggressive view of the mass and perform a total excision rather than an incisional biopsy. Consent was obtained from the patient prior to the procedure. Under local anesthesia, excision of the mass and the extraction of the left lower second molar teeth was performed. The mass was enucleated in its entirety without difficulty. During the enucleation, the mass appeared to have infiltrated the surrounding bone. The surgical area was closed with 6–0 prolen sutures. The patient was given post-operative antibiotherapy. Post-operation for the patient was eventless, with the patient demonstrating no recurrence at the 6-month follow-up appointment.
Histopathological and molecular findings
In histological examination of the OFMT, a proliferation of round to spindle-shaped cells embedded in the myxoid matrix is observed in the sockets and cords. An incomplete mineralized bone trabecular crust is observed just below a fibrous pseudo capsule [ ].
In a macroscopic examination, the OFMT measured 2.5cm in diameter, and appeared as a round yellowish mass circumscribed with a lobulated rubbery cut surface ( Fig. 1 ).
In histological sections the tumor; an unencapsulated, well-circumscribed fibro myxoid tumor was seen. It was incompletely covered with a lamellated shell of bone ( Fig. 2 ).
The tumor is composed of chondroid-like lobules of the spindle or polygonal fibroblastic cells in a myxohyaline background ( Fig. 3 ). Neoplastic cells have bland nuclei with indistinct nucleoli and eosinophilic cytoplasm. Mitotic figures were rare (<2/50hpf). Myxoid stroma contained cellular strands, hyaline bundles, mucinous microcysts ( Fig. 4 ). There was neither invasion outside the main tumor nor necrosis vascular permeation. Immunohistochemically, the tumor shows diffuse S-100 positivity ( Fig. 5 ). Ki-67 activity reached 10% in the hot spots. The histopathologic appearance is accepted as a typical type of ossifying fibro myxoid tumor.