Salivary Neoplasms Classification

Classification of Salivary Neoplasms

• Benign salivary neoplasms:
• Pleomorphic adenoma (mixed salivary tumor)
• Monomorphic adenoma
• Warthin's tumor (adenolymphoma)
• Oncocytoma (oxyphil adenoma)
• Malignant salivary neoplasms:
• Mucoepidermoid carcinoma
• Adenoid cystic carcinoma (cylindroma)
• Acinic cell carcinoma
• Adenocarcinoma
• Carcinoma ex pleomorphic adenoma
• Epidermoid carcinoma (squamous cell carcinoma)
• Lymphoma

Pathology of Benign Salivary Neoplasms

• Pleomorphic adenoma (mixed parotid tumor):
• Represent 75% of parotid and 50% of submandibular gland neoplasms
• Equal distribution between males and females
• Occurs in the fourth decade of life, but any age and sex may be affected
• Pathology:
• Epithelial, myoepithelial, and stromal components
• Incomplete capsule, allowing extension of neoplastic epithelium into surrounding tissues
• Slow growth, non-infiltrating the facial nerve
• Rarely turns into carcinoma after 10 years

Warthin's Tumor (Adenolymphoma)

• Found in the lower part of the parotid gland
• Loss of superficial temporal pulse
• Typically raises the lobule of the ear and does not affect the facial nerve

Differential Diagnosis

• Extra parotid swellings:
• Lymph nodes, sebaceous cysts, and lipomas may resemble pleomorphic adenomas
• Mandibular, maxillary, and infratemporal fossa tumors may produce false appearance of parotid enlargement
• Hypertrophy of the masseter is bilateral in most cases

Investigations

• Not routine, as clinical diagnosis is reliable enough for most cases
• Biopsy:
• FNAC is allowed, but requires an expert cytopathologist
• Open surgical biopsy of major salivary glands is contraindicated
• Neck US
• CT-scan and MRI: to show the extent of the tumor
• Isotope scanning with technetium: salivary neoplasm shows as a cold spot, adenolymphoma and oncocytoma show as hot spots

Treatment

• Surgery is the only reliable form of treatment for salivary neoplasms

Clinical Picture of Benign Salivary Neoplasms

• Symptoms:
• Painless, slowly growing swelling in the parotid region
• Signs:
• Swelling over the angle of the mandible
• Elevates the lobule of the ear
• Swelling is superficial to the masseter muscle
• Facial nerve is not affected by the tumor

Clinical Picture of Benign Salivary Neoplasms (Palpation)

• Swelling is not hot, not tender, not attached to the skin, masseter, or mandible
• Swelling is well-defined
• Consistency: varies from firm to cystic (but never hard)
• Pulsation of the superficial temporal artery is normal

Clinical Picture of Carcinoma of the Parotid

• Symptoms:
• Steadily enlarging swelling on the side of the face
• Salivary malignancies do not usually grow as fast as other cancers
• Swelling is sometimes painful, with pain radiating to the ear and intensified by mastication
• Signs:
• Mass is usually warm and mildly tender
• Firm or hard and has an irregular surface
• May be adherent to the skin, masseter, or mandible
• If the tumor infiltrates the facial nerve, there is weakness or paralysis of the facial muscles
• Cervical lymph nodes are sometimes involved
• Rarely, these tumors metastasize to the lungs