Axillary Lymph Node Metastasis from Thyroid Malignancy: Unusual Presentation with Ominous Implications

Lymph node metastases to cervical group of nodes occur frequently in well-differentiated thyroid carcinoma. Metastasis to axillary lymph nodes however, is exceptional, leading to diagnostic and management dilemma. While presenting a case of thyroid malignancy with axillary lymph node metastasis, the literature is reviewed for similar cases to analyze their clinico-pathological features, investigations, management and outcome. Fifteen cases have been reported so far. Majority of these patients were female (male: female ratio 6:9) and their mean age was 54.5 years. Axillary lymph node metastases occurred concurrently or as recurrent disease after initial treatment of primary disease in about equal number of these patients. The predominant histological type was papillary carcinoma and 83.3% of these were poorly differentiated. Visceral metastases to lungs and bones were often seen. Despite treating these patients with thyroidectomy, lymph node clearance and adjuvant therapy, 40% of them died; some within one year and among the 60% who were alive, 30% still had active disease.
Conclusion: Axillary lymph node metastasis from thyroid cancer, even though rare should be considered in the differential diagnosis in patients presenting with axillary mass and thyroid malignancy. Based on the limited number of cases reported in the literature it appears that it is generally a manifestation of the aggressive nature of this tumor with overall poor outcome.