Selective Neck Dissection in Pleomorphic Adenoma
Selective neck dissection is NOT recommended for benign pleomorphic adenoma, as this is a benign salivary gland tumor that does not metastasize to lymph nodes. 1
Key Distinction: Benign vs. Malignant Disease
Pleomorphic adenoma is the most common benign salivary gland tumor and requires only complete excision of the primary tumor without neck dissection. 1, 2 The surgical approach focuses on adequate removal of the tumor itself—either through superficial parotidectomy or extracapsular dissection—with preservation of the facial nerve. 3, 2
When Neck Dissection IS Indicated: Carcinoma Ex Pleomorphic Adenoma
Selective neck dissection becomes necessary only when pleomorphic adenoma undergoes malignant transformation to carcinoma ex pleomorphic adenoma, particularly when it is high-grade and invasive. 4, 5
Specific Indications for Neck Dissection:
High-grade, invasive carcinoma ex pleomorphic adenoma requires elective neck treatment for cN0 disease, as this histology has >20% rate of nodal involvement at presentation 4, 5
T3-T4 carcinoma ex pleomorphic adenoma mandates elective neck dissection regardless of grade 4
For cN0 disease with high-grade or T3-T4 carcinoma ex pleomorphic adenoma: ipsilateral selective neck dissection of levels II-IV should be performed 4, 6
For cN1 disease: ipsilateral neck dissection of involved and at-risk levels extending to levels I-V is recommended 4, 6
For cN3 disease: comprehensive neck dissection is required 4, 6
Evidence Supporting This Approach:
Research demonstrates that nodal metastases occur in high-grade, invasive carcinoma ex pleomorphic adenoma but not in non-invasive variants. 5 A retrospective study found metastatic disease in 10 patients with high-grade, invasive carcinoma ex-pleomorphic adenoma, but no metastases in patients with non-invasive carcinoma ex-pleomorphic adenoma. 5
Critical Pitfalls to Avoid:
Do not perform neck dissection for benign pleomorphic adenoma—this adds unnecessary morbidity without oncologic benefit 1, 2
Do not underestimate the malignant potential of carcinoma ex pleomorphic adenoma, which behaves aggressively and requires comprehensive oncologic management including neck dissection when high-grade or advanced stage 4, 5
Ensure accurate preoperative diagnosis through fine-needle aspiration or core biopsy, though recognize that distinguishing benign pleomorphic adenoma from carcinoma ex pleomorphic adenoma preoperatively can be challenging 7