Classification of Salivary Neoplasms

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)

• Most common tumor of salivary glands (75% of parotid and 50% of submandibular gland neoplasms)
• Equally distributed between males and females
• Occurs in the fourth decade of life
• Pathology: epithelial, myoepithelial, and stromal components with wide variations in cellular and architectural morphology
• Incomplete capsule that allows extension of neoplastic epithelium into surrounding tissues
• Rarely turns into carcinoma after 10 years

Warthin's Tumor (Adenolymphoma)

• Found in the lower part of the parotid gland
• Represents 15% of all parotid tumors and is bilateral in 10-15% of cases
• Thought to arise from heterotopic salivary tissue in parotid lymph nodes
• Macroscopy: multiple cysts of variable sizes
• Microscopy: epithelial-lined spaces filled with creamy material, surrounded by lymphoid tissue
• Affects elderly people and is related to smoking

Pathology of Carcinoma of Salivary Glands

Mucoepidermoid Carcinoma

• Arises from duct epithelium
• Most common malignant tumor of salivary glands
• Affects the parotid gland
• Three grades: low, intermediate, and high
• Low-grade type is the most frequent and affects children

Adenoid Cystic Carcinoma (Cylindroma)

• Commonest malignancy affecting minor salivary glands
• Histology: alternating layers of cylinders of cells and hyaline material
• Slow rate of growth and perineural spread
• High recurrence rate due to incomplete removal

Acinic Cell Carcinoma

• Uncommon tumor
• Cells resemble acinic cells of the parotid gland
• May metastasize to local lymph nodes or distant sites

Miscellaneous Adenocarcinomas

• Vary according to histologic pattern (trabecular, anaplastic, mucous carcinomas)
• Highly malignant

Clinical Picture of Benign Salivary Neoplasm

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

Clinical Picture of Benign Salivary Neoplasm (continued)

• Palpation:
• Swelling is not hot, not tender, not attached to the skin, masseter, or mandible
• Well-defined borders
• Consistency: varies from firm to cystic (but never hard)
• Parotid Salivary Fistula:
  • May be connected to duct or gland
  • Fistula related to gland is usually related to the lower pole of the parotid
  • Salivary discharge is increased by meals and sucking of a lemon

Treatment of Parotid Salivary Fistula

• Heal spontaneously by granulation tissue
• Use atropine derivatives to decrease salivation
• Irradiation needle inside the fistula to cause fibrosis
• Avulsion of auriculo-temporal nerve to cause atrophy
• Excision of the fistula with the lower part of the gland and close the fascia
• Conservative superficial parotidectomy may be done

Treatment of Parotid Duct Fistula

• Excision and end-to-end anastomosis
• Slitting the opening of the duct proximal to the site of the fistula
• Reimplantation of the fistulous opening to the inner side of the cheek
• Rectangular pedicle flap of mucosa from the inner aspect of the cheek
• Superficial parotidectomy if all else fails