Delayed Diagnosis of Follicular Thyroid Carcinoma with Skull Base and Lung Metastases in a Long-standing Neck Swelling: A Case Report

Follicular Thyroid Carcinoma (FTC) is a differentiated thyroid cancer characterised by haematogenous metastases and the potential for distant metastases. This case report presents a 35-year-old female patient from rural India with a painless, gradually enlarging anterior neck swelling for the last 16 years. The patient presented with compressive and systemic symptoms, including stridor, hoarseness of voice, heat intolerance, and facial asymmetry. Imaging showed a large retrosternal thyroid mass with pulmonary and sphenoid bone metastases. A preoperative diagnosis of thyroid malignancy was made. The patient underwent total thyroidectomy with Level II, III, and IV neck dissection under general anesthesia, and histopathology identified FTC with distant metastases. The postoperative course was uneventful, and she was referred for Radioactive Iodine (RAI) therapy. This case highlights the importance of recognising and intervening early in cases of long-standing thyroid swellings to prevent complications from delayed diagnosis of malignancy.