Abstract

Background: Thyroid nodules are frequently encountered, with 5%-10% being malignant. Follicular thyroid carcinoma (FTC) is a differentiated thyroid malignancy, known for hematogenous spread to distant sites such as lungs, bones, and less commonly, soft tissues. We report a rare case of FTC with isolated metastasis to the scapula.
Case Description: A 55-year-old female initially presented with a thyroid mass. A diagnostic workup followed by FNAC revealed follicular neoplasm. The patient underwent a right lobectomy and then a total thyroidectomy. The patient was diagnosed with follicular carcinoma on biopsy and was given radioactive iodine (RAI) therapy. The patient was on regular yearly follow-up for 6 years and then lost to follow-up for 3 years due to the corona pandemic. Despite initial treatment and maintenance on levothyroxine, she presented nine years later with a painful, enlarging mass in her right shoulder. Imaging (X-ray, CT, and MRI) and ultrasound-guided core biopsy were performed to diagnose the lesion.
Results: Imaging revealed a large, infiltrative malignant lesion in the right scapula, causing extensive bone and muscle destruction. Biopsy confirmed metastatic FTC. The second therapeutic dose of 200 mCi of radio-iodine (I-131) was given. Post therapy scan showed significant radioiodine uptake in the scapula, indicating active metastatic disease. The patient was then treated with monthly injections of Zometa for bone strengthening and continues to be monitored.
Conclusion: This case underscores the necessity for vigilant long-term follow-up in FTC patients due to the potential for late metastatic presentations. The multidisciplinary approach, involving imaging, pathology, and nuclear medicine, is crucial for accurate diagnosis and effective management of metastatic FTC. This case highlights the role of appropriate counseling of the patient regarding the need for long-term follow-ups, keeping in mind the possibility of distant metastasis late after the initial presentation.

Key words: Follicular thyroid carcinoma, scapular metastasis, thyroglobulin, fine needle aspiration cytology (FNAC), thyroidectomy, case report.