A rare case of cementifying fibroma of the mandible: a histopathological study

Background. Benign fibro-osseous lesions are characterized by the replacement of normal bone tissue with connective tissue that undergoes varying degrees of mineralization. The main forms of fibro-osseous lesions include fibrous dysplasia, cemento-osseous dysplasia, and various variants of ossifying fibroma, such as cemento-ossifying and cementifying fibroma. Fibro-osseous lesions have similar clinical symptoms, radiographic, and histological features. These lesions are a diagnostic problem for maxillofacial surgeons and pathologists. Therefore, a comprehensive evaluation of these lesions will help to avoid diagnostic errors and ensure a correct diagnosis, which will guarantee the correct treatment and an informative prognosis. Objective: to establish the histopathological features of a rare case of cementifying fibroma of the mandible for differential diagnosis with other fibro-osseous lesions and to determine prognosis. Methods. We present a rare case of cementifying fibroma of the mandible in a 34-year-old patient after diagnostic examination and surgical treatment at the Clinic of Surgical Dentistry and Maxillofacial Surgery of the Danylo Halytsky Lviv National Medical University. We conducted a histopathological study of the postoperative material obtained after revision of the pathological lesion on the left mandible, excision of the neoplasm and curettage. The jaw tissue samples were fixed in 10% neutral buffered formalin solution, then decalcified with subsequent dehydration in alcohols of increasing concentration and embedded in paraffin. Histological sections with a thickness of 5±1 μm were made from paraffin blocks on a Leica RM2235 rotary microtome, then stained with hematoxylin-eosin according to the standard method. Diagnostics were performed on a Leica DM750 microscope (Leica Microsystems GmbH). Results. The microscopic picture showed multiple small fragments of connective tissue with fibroblasts and a small number of vessels. The fibrous-cellular stroma was characterized by a predominance of chaotically arranged spindle-shaped and stellate cells with basophilic hyperchromic nuclei and a minimal amount of cytoplasm. Among the connective tissue were numerous rounded, irregularly shaped and confluent calcified complexes of the cementum type without osteoblast reaction. In addition, a small number of calcified bone beams with osteoid and osteoblasts were found. Orthopanotomogram showed a radiolucent well-defined image in the region of 37,38 and in the angle of the mandible. Conclusion. Cementifying fibroma, as a mesenchymal benign odontogenic tumor of the jaws, originates from mesenchymal blast cells of the periodontal ligament and forms a combination of cement-like tissue and fibrous cellular tissue. Diagnosis of cementing fibroma is based on clinical and radiological findings of the lesion, and histological examination confirms the diagnosis.