Benign neoplasms of bone – Osteomas
Osteomas are benign neoplasms of bone (osseous tissue), which are consisting of either mature compact bone or cancellous bone. These neoplasms are almost exclusively found in the craniofacial region.
Osteomas are of two types:
Periosteal osteoma: Lesions arising peripherally from the outer surface of the bone.
Endosteal osteoma: Lesions arising centrally within the medullary region of bone.
Age: Second to fifth decade of life.
Sex: More frequent among females.
Site: Osteomas occur either peripherally or centrally in relation to any bone of the cranium and the face, few lesions also develop from within the sinus cavities.
Some lesions may arise from the soft tissues, e.g. tongue or buccal mucosa, etc.
Jawbones are often affected and interestingly osteomas often develop from those areas of the jaw from where tori usually do not arise. Body of the mandible in the molar region (lingual surface) is the most favored location of this tumor.
• Osteoma often produces an asymptomatic, slow growing, nodular, exophytic, bony hard growth in the jaw (Fig. 2.84).
• The lesion can be either solitary or multiple and the overlying skin or epithelium appears
• Larger lesions of osteomas may cause facial deformity, with expansion of the cortical plates of bone and displacement of the regional teeth (Fig. 2. 85).
• Osteomas developing over the condyle of mandible often cause pain, decreased mouth opening, deviation of chin and derangement of occlusion, etc.
• Multiple osteomas often occur in association with Gardner syndrome, a hereditary condition with an autosomal dominant pattern.
• The syndrome also consists of multiple intestinal polyps with malignant potential, many unerupted normal or supernumerary teeth, epidermoid cyst and desmoid fibromas of skin.
• Osteomas of the maxillary antrum (Fig. 2.86) may predispose to sinusitis, which produces pain in the maxillary molar area with nasal discharge.
RADIOGRAPHIC FEATURES (FIG. 2.87)
Osteomas radiographically present well circumscribed, solitary or multiple, round or oval, dense radiopacities in the bone. Larger lesions (endosteal type) cause expansion of the cortical plates and the peripheral outline or the border of the lesion is generally sclerotic.
Microscopically osteoma presents the following features (Figs 2.88 and 2.89):
• The lesion is composed of dense cortical bone with a distinct lamellar pattern.
• The cortical bone is sclerotic and relatively avascular.
• The medullary bone is denser than normal bone with reduced marrow spaces.
• The marrow spaces are composed of areolar fibrous tissue or adipose tissue.
• The periosteal layer is often more active in case of osteoma than the normal bone.
• When multiple osteomas occur, each discrete ossified mass is separated from one another by a mature fibrous tissue stroma.
• Sclerotic cemental masses
• Focal sclerosing osteomyelitis.
Surgical excision. Antral lesions are removed by Caldwell-Luc approach.