Pattern of cervical lymph node metastasis in medial wall pyriform sinus carcinoma.

OBJECTIVES/HYPOTHESIS: The aim of this study was to analyze the prevalence and distribution of histologic cervical lymph node metastases in medial wall pyriform sinus squamous cell carcinoma (SCC). STUDY DESIGN: Retrospective study of medical records. METHODS: We reviewed the medical records of 68 medial wall pyriform sinus SCC patients who underwent bilateral neck dissection for primary treatment with curative intent. Thirty-nine patients underwent central compartment neck dissection. Primary tumor was removed using conservative laryngeal surgery with partial pharyngectomy in 39 cases, near total/total laryngectomy with partial pharyngectomy in 24 cases, and total laryngopharyngectomy in five cases. RESULTS: The overall N(+) contralateral lymph nodes rate on pathology was 14.7%. The rate of contralateral occult cases was 5.2%. Advanced primary (T3-4) and nodal (N2b-3) disease, and primary lesion across the midline were correlated with contralateral nodal metastasis. Multivariate analysis revealed that a primary lesion across the midline was an independent factor for contralateral neck nodal metastasis. The rate of level VI node metastasis was 16.2%. The disease-specific survival rate was significantly different according to level VI node metastasis (71% vs. 40%). Pyriform sinus apex invasion and extralaryngeal spread were correlated with level VI nodal metastasis. Multivariate analysis revealed that pyriform sinus apex invasion was an independent factor for level VI nodal metastasis. CONCLUSIONS: Contralateral nodal metastasis was less frequent than expected. Bilateral neck dissection is mandatory for primary lesion across the midline. Ipsilateral level VI lymph node should be removed in pyriform sinus apex invasion cases. LEVEL OF EVIDENCE: 4.