Metastasis of Non-Muscle-Invasive Bladder Cancer Into the Thyroid Gland: A Literature Review Accompanied by a Rare Case
An 83-year-old male patient visited the Urology Department with complaints of macroscopic hematuria at intervals over 9 months. Transurethral resection of the bladder (TUR-B) was performed on the patient when a 17-mm×14-mm mass was found in the ultrasound examination. The pathological result was a high-grade superficial papillary urothelial carcinoma (). Repeat TUR was applied to the patient 4 weeks later and high-grade urothelial carcinoma with lamina propria invasion was found, whereas muscularis propria invasion did not exist. Positron emission tomography (PET) was performed during the second month because the patient had chest pain in the postoperative period, and multiple metastatic bone lesions, metastatic lymphadenopathies on the mediastinum and right external iliac area, a hypermetabolic lesion on the left thyroid lobe, and a hypermetabolic lesion on the left adrenal gland were found. Incisional biopsy performed on the fifth rib of the patient was evaluated as urothelial carcinoma metastasis and radiotherapy was applied to the patient for these lesions ().\nIn the physical examination of the patient, a fixed, 3-cm mass was palpated on the left lobe of the thyroid. Then, in the neck computed tomography (CT) with contrast, a 40 mm×34 mm nodular mass was found on the left lobe of the thyroid gland, which caused left-sided destruction of the thyroid cartilage. The mass was evaluated as a hypoactive nodule in thyroid scintigraphy. A hypermetabolic nodular lesion was seen on the left thyroid lobe by PET. Malignant tumor cells were observed in the fine-needle aspiration sample taken from the hypermetabolic lesion on the left lobe of the thyroid. Owing to the patient's clinical history, primary thyroid carcinomas were considered in the differential diagnosis, because metastatic carcinoma and anaplastic and medullar carcinomas are of first priority. The immunohistochemical panel included thyroid transcription factor-1 (TTF-1) and thyroglobulin in terms of thyroid tumors; calcitonin, carcinoembryonic antigen (CEA), chromogranin A, and synaptophysin in terms of medullar carcinoma; and cytokeratins (CK) 7 and CK 20 antibodies in terms of urothelial carcinoma. No reaction was observed with neuroendocrine markers (synaptophysin and chromogranin), calcitonin, thyroglobulin, or TTF-1 in tumoral cells. Positivity was established in some cells by CEA and CK 20. The tumor was evaluated as a urothelial carcinoma metastasis owing to the clinical history of the patient, the existence of other metastases, the morphological similarity of the tumor cells with the primary tumor, and CK 20 positivity in some cases immunohistochemically (). Because the general condition of the patient worsened while planning chemotherapy, no systematic chemotherapy was applied. After 6 months, the patient died.