Endocrine Abstracts

JOINT3976

Introduction: Differentiated thyroid cancer has a good prognosis and survival rate. Oncocytic thyroid cancer (formerly known as Hürthle cell carcinoma) is generally considered to be less radioiodine-avid compared to other types of differentiated thyroid cancers. Clinically, oncocytic thyroid cancer is characterized by a higher incidence of locoregional recurrence than follicular thyroid cancer (FTC) and a higher incidence of distant metastases than in papillary thyroid cancer (PTC). Metastases of thyroid cancer to the brain are extremely rare and are usually associated with other typical metastatic locations (lung and bone).

Case Report: We present the case of a patient with a more than 50-year history of thyroid cancer. In 1969, the patient, then 17 years old, underwent a strumectomy for goiter. The documentation contained information about a Hürthle cell adenoma. Seven years later, in 1976, a total thyroidectomy was performed, and in the same year, chemotherapy was started in the Department of Haematology and Oncology. Between 1976 and 1977, the patient received chemotherapy based on 5-fluorouracil, cyclophosphamide, and doxorubicin for 16 months. In 1977, the patient underwent diagnostic scintigraphy with radioiodine I-131—no radioiodine uptake was visualized. Three years later, in 1981, a chest X-ray described multiple lung tumors that persisted for almost 20 years without treatment. In 2023, 54 years after the initial diagnosis, an MRI was performed after the onset of neurological symptoms and showed a lesion in the left occipital region measuring 60×42×52 mm. A craniotomy was performed and the tumor was removed; the course of the operation was complicated by a hematoma, and a reoperation was performed on day 2. A histopathological examination confirmed metastatic thyroid carcinoma from Hurthle cells. This was followed by radiotherapy to the locoregional area, with a total dose of 3000 cGy. Subsequently, treatment with radioiodine I-131 was carried out twice (total activity of 7,4 GBq). Posttherapeutic scintigraphy showed no uptake in the brain region and revealed pathological uptake in numerous diffuse foci in both lungs confirmed in CT scan of the chest. The patient remains in good condition, ECOG 1, without neurological symptoms.

Conclusions: The atypical course of the disease indicates a generally good prognosis in thyroid cancer, a slowly progressive course of lesions, and the possibility of metastasis many years after the initial diagnosis. CNS metastasis is rare, but should always be considered, especially if other lesions coexist.