THYROID CARCINOMA METASTASES TO AXILLARY LYMPH NODES: REPORT OF TWO RARE CASES OF PAPILLARY AND MEDULLARY THYROID CARCINOMA AND LITERATURE REVIEW

Objective: Axillary lymph nodes (ALNs) are a rare manifestation of thyroid carcinoma; only 16 cases are in the published literature. This study adds two additional patients, one involving differentiated papillary thyroid carcinoma (PTC) and one case involving medullary thyroid carcinoma (MTC). The limited information on this topic in the literature is also reviewed. Methods: In case 1, a 56-year-old female diagnosed in 2004 with stage IV PTC (lung and rib metastases) underwent total thyroidectomy (TTx) and received radioiodine and antineoplastics for progression in the lung, liver, and chest wall (2008-2011). In 2012, screening mammography detected multiple axillary masses corresponding to ALNs on magnetic resonance imaging. After fine-needle aspiration biopsy demonstrated metastatic PTC, the patient underwent right ALN dissection and is currently with stable disease. In case 2, a 59-year-old male diagnosed in 2011 with stage III MTC underwent TTx and bilateral modified lymph node (LN) dissection for cervical LN metastases. Three months later, a positron emission tomography scan revealed hypermetabolic ALNs confirmed by excisional biopsy as metastatic MTC. A completion left ALN dissection and supraclavicular LN excision was performed and the patient is currently with stable disease. Results: Sixteen reports of ALN metastases from thyroid cancer exist in the literature: 11 PTC, 2 mucoepidermoid carcinoma variants, and 1 each of follicular thyroid carcinoma, MTC, and poorly differentiated mucin-producing adenocarcinoma. This study reports the second case of MTC metastatic to ALNs. Conclusion: Thyroid cancer ALN metastases are rare representations of distant metastatic disease. Complete surgical resection remains the standard of care for all MTC metastases and for DTC patients with local symptoms or otherwise stable disease that can tolerate the operation.