its incidence worldwide is 10.1 in every 100,000 men and 2.5 in every 100,000 women . the highest incidence rate of bladder cancer in europe is seen in the western and southern regions , whereas eastern europe has the lowest incidence rate . the worldwide mortality rate is 4 in every 100,000 men and 1.1 in every 100,000 women . the mortality rate of bladder cancer in europe in the past decade was 16% in men and 12% in women . seventy percent of cases of newly diagnosed disease are superficial disease ; roughly 30% of newly diagnosed cases are muscle - invasive metastatic diseases . although local recurrence is significant despite treatment , the natural progression of non - muscle - invasive bladder cancer tends to remain superficial . about 5% to 20% of superficial tumors will develop into muscle - invasive disease despite treatment . the most common areas of distant metastases of urothelial carcinomas are typically the liver , lung , mediastinum , bone , and adrenal gland , respectively . we present a case of non - muscle - invasive bladder cancer that metastasized into the bone , mediastinum , iliac lymph node , and adrenal and thyroid glands . 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-mm14-mm mass was found in the ultrasound examination . 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 ( fig . 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 mm34 mm nodular mass was found on the left lobe of the thyroid gland , which caused left - sided destruction of the thyroid cartilage . 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 . 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 ( fig . because the general condition of the patient worsened while planning chemotherapy , no systematic chemotherapy was applied . the prognosis and survival of patients with bladder cancer are associated with stage and grade during diagnosis . survival rates for 5 years were reported as 94% for grade 1 non - muscle - invasive disease , 40% for grade 3 non - muscle - invasive disease , 72% for stage t2 , and 33% for stage t4 muscle - invasive disease . contrary to muscle - invasive disease , many superficial bladder cancers can be treated by regular monitoring cystoscopy , urinary cytology , and re - tur together or not with protective therapy , transurethral resection , and adjuvant intravesical treatment . despite these measures , about 5% to 20% of non - muscle - invasive tumors will progress to muscle - invasive disease . high - grade non - muscle - invasive tumors are related to a high risk of muscular invasion and metastasis and end up with a worse prognosis . also , it is known that metastasis can appear without muscular invasion ; these metastases are found in regional lymph nodes during cystectomy . cases of distant metastasis of low - grade non - muscle - invasive urothelial carcinoma without regional lymph node metastasis have been reported . errors in clinical staging of bladder tumors are well known . in some pathological staging cases , it is estimated that low staging was done at a rate as high as 30% to 40% . the european organisation for research and treatment of cancer ( eortc ) developed a scoring system and a risk table to estimate short- and long - term risks of recurrence and progression separately . in this scoring system , clinical and pathological parameters are tumor number , tumor size , previous recurrence rate , t phase , carcinoma in situ presence , and tumor grade . in our patients , possible mean progression rates according to the score are reported as 5% in the first year and 17% in the fifth year . in the eortc study , no results are reported for new concepts such as re - tur , early single - dose chemotherapy , and maintenance bacillus calmette guerin treatment , and this has been criticized by authors . in our patient , early single - dose chemotherapy and re - tur were applied and both pathology reports suggested a high - grade non - muscle - invasive bladder tumor . although the progression rate of our patient for 1 year was estimated as 5% according to the eortc study , progression developed in the patient before initiating induction treatment of intravesical ct and before symptoms associated with bone metastases developed . there are publications in the current literature that report that low - grade non - muscle - invasive bladder tumors are detected clinically and the distant lung metastasis can appear without regional lymph node involvement . rare metastases of urothelial carcinoma into the skin , uterus , and orbita and vaginal and omental involvements have also been reported . .   showed a small cell carcinoma that metastasized into the thyroid gland , which is a minor variant of bladder urothelial carcinoma . small - cell carcinoma is rarely originated from the bladder and comprises of 0.48% to 1% of all bladder tumors . metastases in the thyroid gland are observed in many patients by physical examination or imaging methods during routine monitoring after primary tumor resection . in these patients , fine - needle aspiration may be useful for evaluating possibilities and limiting unnecessary operation for diagnostic purposes . the most significant conflict in cytologic comment is the differentiation between primary thyroid anaplastic carcinoma and high - grade metastatic malignity . in the fine - needle aspiration material of the patient , differential thyroid carcinomas and medullar carcinomas can be excluded morphologically and immunohistochemically . in the present case , no reaction was observed with neuroendocrine markers ( synaptophysin and chromogranin a ) , calcitonin , thyroglobulin , or ttf-1 in tumoral cells . although a positive reaction immunohistochemically with thyroglobulin supports a primary thyroid malignancy , only 20% to 30% of anaplastic carcinomas display thyroglobulin positivity and negative results do not have meaning . because 20% to 30% of anaplastic carcinomas display thyroglobulin positivity and negative results do not have meaning the patient 's clinical history is the most essential part in the differential diagnosis of these lesions , and it is emphasized that a thyroid nodule found in a patient with a known cancer should be accepted as metastasis unless proven otherwise . because our patient had a known urothelial carcinoma history , other metastases , a morphological similarity between the tumor cells and the primary tumor , and ck 20 positivity immunohistochemically in some cells , the tumor was evaluated as a urothelial carcinoma metastasis . in conclusion , non - muscle - invasive bladder tumors may present with multiple distant metastases even without muscle invasion . this presented case showed that bladder tumors can metastasize into the thyroid gland in addition to known distant metastasis areas . metastasis of a bladder tumor should also be kept in mind in the differential diagnosis in patients who have a bladder tumor history and are found to have a mass on the thyroid gland .