Late Onset of an Overlooked Follicular Thyroid Carcinoma Presenting as a Chest Wall Tumor 10 Years Following Thyroidectomy

OBJECTIVE: Metastatic chest wall tumors resulting from thyroid carcinomas are not unusual; however, the late onset of metastasis of a follicular thyroid carcinoma (FTC) is extremely rare. We aim to present a report of a case with chest wall metastasis of an FTC 10 years following thyroidectomy. METHODS: Among the studies performed were chest wall tumor imaging, serum thyroid stimulating hormone determination, and histopathology of the chest wall tumor and thyroid tissue examination. RESULTS: An asymptomatic 28-year-old woman was noted to have a left-sided chest wall mass on a chest X-ray performed for a job application. She had a history of right hemithyroidectomy 10 years prior to her admission, which had been reported as a thyroid follicular adenoma. Computed tomography showed a tumor measuring 75 × 50 mm in diameter localized at the left paravertebral region. The maximum standardized uptake value of the tumor was seven in positron emission tomography. Histopathologic finding of the trucut biopsy of the chest wall tumor revealed metastasis of a differentiated thyroid carcinoma. The patient underwent a completion left hemithyroidectomy with chest wall resection and reconstruction. Previous right hemithyroidectomy material was examined and diagnosed as minimally invasive FTC. Histopathologic finding of the resected chest wall tumor was consistent with metastasis of an FTC. CONCLUSIONS: Although extremely rare, the late metastasis of a thyroid carcinoma should be considered in the differential diagnosis of patients with chest wall tumors who have a previous history of thyroidectomy even with a diagnosis of benign tumor.