Ossifying Fibroma Of Non-odontogenic Origin

Ossifying Fibroma Of Non-odontogenic Origin

Question. Write a short note on ossifying fibroma.
Answer. Ossifying fibroma is a benign fibro-osseous neoplasm which is non-odontogenic, well-defined, and is rarely encapsulated, consisting of fibrous tissue with various amounts of mineralized material which is similar to bone or cementum.

Ossifying Fibroma Clinical Features

• It is seen during the third or fourth decades of life, with females more commonly affected.
• It can arise from any part of the facial skeleton and skull. The lesion is seen principally in the jaw, but is also seen in orbitofrontal bone, nasopharynx, paranasal sinus, and base of skull. Premolar-molar area is mostly affected in the mandible above the inferior alveolar canal. In the maxilla, it often occurs in the canine fossa and zygomatic arch region.
• Facial asymmetry is seen in some of the cases.
• In the maxilla, symptoms are nasal stuffiness and epiphora of the affected side.
• The signs present are exophthalmos with visual disturbances, these depends on extent of compression of its orbital content by tumor.
• The lesion grows slowly along with the displacement of teeth.
• Bony cortex and covering mucosa remain intact along with cortical expansion.
• Initially, the lesion is slow growing with rapid increase in size, usually in a shorter duration of time.

Ossifying fibroma of non-odontogenic origin

Ossifying Fibroma Radiographic Features

• Borders of the lesion are well defined. Usually, a thin radiolucent line, represents the fibrous capsule that separates it from the surrounding bone. At times, the bone present next to the lesion develops a sclerotic border.
• During the early stage, solitary cyst-like osteolytic lesions are seen, which are present without the periosteal reaction. In this type, where abnormal bone is present, the pattern is the same as seen in fibrous dysplasia, or either a wispy or flocculent pattern is seen. Lesions which produces more of cementum-like material can consist of solid amorphous radiopacities i.e., cementicles which are same as seen in cemental dysplasia. The lesion shows a mixed radiopaque/radiolucent appearance.
• Growth of the tumor is concentric inside the medullary part of bone with outward expansion which is equal in all directions. The lesion can grow and occupy the complete maxillary sinus, expanding its wall in an outward direction; moreover, a bony partition is appreciated between the internal aspect of the remaining sinus and the tumor. If it involves the orbit, it can displace the globe.
• Expanding lesion shows displacement of teeth. The lamina dura of the involved teeth is missing. Resorption of teeth can be seen.

Ossifying Fibroma Diagnosis 

• Clinical diagnosis: This is not specific; only facial symmetry is appreciable.
• Radiological diagnosis: Lesion shows mixed radiopaque/radiolucent appearance along with the presence of a sclerotic border. Teeth displacement can also be appreciated.
• Laboratory diagnosis: Here connective tissue stroma shows cellular fibrous connective tissue, which consists of cementum-like spherules. Fibroblasts are present in abundance with flat and elongated nuclei inside the network of interlacing collagen fibers.

Non-odontogenic ossifying fibroma

Ossifying Fibroma Differential Diagnosis

During the Early Radiolucent Stage

• Primordial cyst: Associated with a missing permanent tooth, which is not seen in an ossifying fibroma.
• Residual cyst: A Previous history of extraction is seen.
• Ameloblastoma: This is seen in the posterior region of the mandible, and there is the presence of paresthesia of the lip. It also has a multilocular appearance.
• Periapical cemental dysplasia: Its most common site is the apices of vital teeth. It is seen in the mandibular incisor region, while cementifying fibroma is seen commonly in the premolar-molar region.
• Adenomatoid odontogenic tumor: It is always associated with impacted maxillary canines in young patients.

Mixed Radiopaque Radiolucent Lesion

• Calcifying epithelial odontogenic tumor: It is commonly located in the posterior body and ramus of mandible.
• Osteoid osteoma: Seen commonly in males under 30 years of age and not seen so frequently in the jaws, while ossifying fibroma is seen commonly in jaws and is seen commonly in females during the 3rd or 4th decades of life. It leads to pain at night while an ossifying fibroma remains asymptomatic.
• Osteoblastoma: Its location in the head and neck region is very rare.
• Osteosarcoma: It shows aggressive growth, cortical bone destruction, invades the surrounding soft tissues and along periodontal ligament, while an ossifying fibroma shows benign growth.
• Paget’s disease: It shows a characteristic cotton wool appearance as well as enlargement of the affected bone.
• Fibrous dysplasia: It shows a homogeneous radiopaque region with internal architecture which is granular and obliterates normal bone space. It consists of ill-defined borders and blends in surrounding normal bone.
• Benign cementoblastoma: This occurs during the second and third decades of life in the posterior mandibular region. It is attached to the part of root with the frequent root resorption. Ossifying fibroma is not attached to the roots, but yes, it absorbs the roots.

Nasal cavity ossifying fibroma

Ossifying Fibroma Mature Stage

• Condensing osteitis: It commonly occurs at the periapex of a nonvital tooth. Radiolucent rim is absent.
• Complex odontoma: It has non-uniform density, and this seldom occurs periapically.
• Periapical idiopathic osteosclerosis: This commonly occurs in vital teeth in the periapical region. Ossifying fibroma is smoothly contoured and is round or ovoid, while the periapical idiopathic osteosclerosis is irregular in shape and lacks a radiolucent rim.
• Periapical spherical type of hypercementosis: It remains attached to the part of the root and gets separated from the periapical bone by a radiolucent periodontal ligament space which surrounds the complete root.

Nasal cavity ossifying fibroma

Ossifying Fibroma Management

• Enucleation: Small encapsulated lesions are treated by conservative enucleation.
• Resection: If inferior border of mandible is involved or if the tumor extend into the maxillary sinus.