Endocrine Abstracts

Introduction: Follicular thyroid carcinoma typically spreads through the hematogenous route, causing distant metastases, with bone and lung being the most frequent sites, while metastases to the liver and skin are less common. We report a case of reassessing the diagnosis of follicular thyroid carcinoma due to the identification of flesh-colored skin nodules, later confirmed as cutaneous metastases.

Case presentation: An otherwise healthy 60-year-old man underwent subtotal right thyroidectomy due to clinical suspicion of malignancy in 2016, but the histopathological examination of the resected tissue did not confirm the diagnosis, and the patient chose not to persue follow-ups. Six years later, our patient presented with cutaneous, asymptomatic nodules in the digastric region and in the occipito-parietal and fronto-parietal scalp. Histopathological examination confirmed metastatic follicular thyroid carcinoma. The remaining thyroid tissue was resected, and subsequent histopathological examination revealed no signs of malignancy. A second examination of the previously resected thyroid tissue (in 2016) was conducted, reclassifying the lesion as malignant and confirming it as follicular carcinoma. Further radiological investigations were then performed, detected multiple hepatic, pulmonary, and bone metastases. The patient was then referred to our department for radioactive iodine therapy (RAI), recieved a dose of 100 mCi. A postoperative radionuclide thyroid uptake scan revealed findings consistent with a metastatic lesion in the crane, right scapula, chest, liver, the whole pelvis, both humeri, the proximal-third of the right femur and multiple staged lesions in the bone spine.

Conclusion: This case underscores the diagnostic challenges and harmful consequences of misdiagnosing follicular thyroid carcinoma. It also highlights the well-established role of radioactive iodine therapy in managing high and intermediate recurrence risk FTCs, both therapeutically and diagnostically, as well as the importance of post-thyroidectomy follow-up care.