Histopathological Features of Oral and Maxillofacial Lesions

Bone Lesions

Cemento-ossifying Fibroma

• Masses of poorly cellular cementum
• Fibro-cellular connective tissue

Central Giant Cell Lesion

• Multinucleated giant cells
• Areas of hemorrhage
• Loose vascular connective tissue rich in mononuclear cells

Facial Fibrous Dysplasia: Osseous Stage

• Dysplastic fibrous tissue
• Trabeculae of woven bone without peripheral osteoblastic rimming
• Trabeculae are equidistant from each other, taking the shape of C, U, or W letters (Chinese letter appearance)
• Retraction of dysplastic fibrous tissue from woven bone trabeculae
• Presence of blood vessels

Facial Fibrous Dysplasia: Osteoid Stage

• Trabeculae of osteoid bone laid down equidistant from each other
• Characteristic C, U, or W letter shapes and Chinese letter appearance

Malignant Neoplasms

Fibrosarcoma

• Malignant fibroblasts and proliferating spindle-shaped fibroblasts
• Elongated and deeply stained nuclei arranged in a whorled pattern
• Thin-walled, dilated blood vessels
• Whorled pattern of neoplastic fibroblast cells

Moderately Differentiated Squamous Cell Carcinoma

• Nests of neoplastic cells
• Presence of keratin pearls

Well Differentiated Squamous Cell Carcinoma

• Prominent keratin pearls
• Nests of neoplastic, well-differentiated cells

Premalignant Lesions and Conditions

Carcinoma in Situ

• Severe epithelial dysplasia with top-to-bottom changes and lateral spread
• Basilar hyperplasia and loss of polarity in basal cells
• Cellular and nuclear pleomorphism
• Nuclear hyperchromatism and increased nuclear-cytoplasmic ratio
• Loss of adhesion

Leukoplakia

• Mild epithelial dysplasia
• Nuclear hyperchromatism
• Intact basement membrane

Dental Pathology

Caries in Dentin

• Liquefaction focus
• Transverse clefts
• Areas of dentinal destruction

Salivary Gland Tumors

Pleomorphic Adenoma

• Fibrous capsule of variable thickness
• Duct-like structures containing mucin
• Masses of benign neoplastic epithelial cells
• Areas of myxoid matrix
• Duct-like structures formed of inner neoplastic epithelial cells and an outer layer of myoepithelial cells
• Hyalinized stroma and presence of fat cells

Adenoid Cystic Carcinoma

• Hyalinized stroma
• Malignant, monotonous basaloid cells with hyperchromatic nuclei
• Cells arranged in a cribriform pattern
• Neoplastic basaloid cells arranged in a tubular pattern
• Solid sheets of monotonous malignant basaloid cells

Mucoepidermoid Carcinoma

• Duct-like structures containing mucin or keratin
• Masses of neoplastic epidermoid cells
• Presence of mucous secreting cells
• Duct-like structures formed by both epidermoid and mucous secreting cells