ENT (Otorhinolaryngology) · MU Sofia

49. Tumors of the parotid gland. Types of parotidectomies.

Covers parotid tumours, starting with the gland's anatomy and the facial nerve dividing it into superficial and deep lobes, then aetiology, benign and malignant types, clinical features and red flags for malignancy. It goes on to diagnostics such as cytology, ultrasound, MRI and CT, treatment, and the five types of parotidectomy, with surgical steps, complications and differential diagnosis. It includes two pictures and a classification-style list of parotidectomy types.

Inside: 1 section · 2 labelled pictures · 13 flashcards · 5 min

Topic 49 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 1 section, about 690 words (5 min of reading), with 13 flashcards.

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  1. Tumors of the parotid gland. Types of parotidectomies.

Tumors of the parotid gland. Types of parotidectomies.

1. Definition - Parotid tumors are abnormal growths arising from the epithelial or connective tissue of the parotid gland. Due to the gland's anatomy, the Facial Nerve (CN VII) divides the gland into a "superficial lobe" and a "deep lobe," which is a critical surgical consideration. ~80% are benign, and parotid is the most commonly involved salivary gland. Largest gland. Preservation of the facial nerve is the most important surgical principle.

2. Etiopathogenesis

  • Genetic Factors: Chromosomal rearrangements (eg, PLAG1 in pleomorphic adenomas).
  • Radiation: History of ionizing radiation to the head and neck increases the risk of both benign and malignant tumors.
  • Smoking: Strongly associated with Warthin's Tumor.
  • Viral: EBV or HIV can lead to lymphoepithelial lesions.

Pathogenesis involves:

  • Neoplastic transformation of ductal epithelial or myoepithelial cells
  • Malignant tumors show perineural invasion and infiltrative growth

3. Classification

Benign Tumors (Most Common) (≈80%)

  • Pleomorphic Adenoma (Benign Mixed Tumor): The most common parotid tumor. It has a high risk of recurrence if the capsule is breached and a small risk of malignant transformation (Carcinoma ex-pleomorphic adenoma). Slow-growing

Firm, painless mass

  • Warthin's Tumor (Adenolymphoma): Often found in older male smokers; frequently bilateral or multicentric. Often cystic.

3. Other benign tumors

  • Hemangioma
  • Lipoma
  • Oncocytoma

Malignant Tumors

  • Mucoepidermoid Carcinoma: The most common parotid malignancy.
  • Adenoid Cystic Carcinoma: Known for perineural invasion (spreading along nerves) and late distant metastasis.
  • Acinic Cell Carcinoma.
  • Carcinoma ex-pleomorphic adenoma.

4. Clinical Picture

  • Benign Tumors: painless, slow-growing parotid swelling, mobile, firm mass, no facial nerve palsy.
  • Signs of Malignancy (Red Flags):
  • Facial Nerve Palsy: Any weakness of the facial muscles strongly suggests malignancy.
  • Rapid Growth: Or sudden increase in size of a long-standing lump.
  • Pain and Skin Fixation: Or ulceration of the overlying skin.
  • Hard, Fixed Consistency.
  • Cervical Lymphadenopathy.

5. Paraclinical and Radiological Examinations- clinical exam

  • Fine Needle Aspiration Cytology: The diagnostic gold standard. It differentiates benign from malignant and guides surgical planning. Open biopsy is strictly contraindicated due to the risk of tumor seeding and facial nerve injury.
  • Ultrasound: Useful for distinguishing solid from cystic lesions.
  • MRI (Preferred): Superior for soft tissue. It helps determine the relationship between the tumor and the facial nerve and identifies deep lobe involvement.
  • CT scan: Better for evaluating cortical bone invasion.

6. Treatment Options

  • Benign Tumors: Surgery is treatment of choice
  • Superficial parotidectomy (most common)- Removal of superficial lobe
  • Preservation of facial nerve
  • Malignant Tumors:
  • Total parotidectomy- Removal of both superficial and deep lobes

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