Abstract
Background : We report a case of basaloid squamous cell carcinoma (BSCC) arising from the ureter.
Case : A man in his 80 s, who was referred to the urology department of our hospital for left hydronephrosis. Urinary cytology revealed atypical cells and postoperative histopathological examination after transurethral tumor resection revealed the diagnosis of BSCC. Therefore, we performed complete left nephroureterectomy and fine-needle aspiration cytology of the tumor. The tumor was composed of cells that were either scattered or occurred in loosely connected sieve-like aggregates ; the nuclei were uniform and round-to-oval in shape and the nuclear chromatin was finely granular. The cribriform cells occurred in a myxoid-like extracellular matrix, which is known to be a characteristic of adenoid cystic carcinoma. Histological examination of the resected specimen after total left nephroureterectomy revealed a protuberant lobulated mass measuring 4.7×3.4×3.2 cm in size in the lower left ureter, near the bladder inlet, that filled the ureter and showed ascending growth. Infiltrative and proliferative tumor cells resembling basal cells and forming cribriform alveoli were observed. Immunohistochemical analysis revealed positive immunostaining of the alveoli consisting of basaloid cells for p40 and p63, based on which the tumor was diagnosed as a basal adenoid squamous cell carcinoma (adenoid cystic features).
Conclusion : BSCC arising from the urinary tract is extremely rare, so that it is necessary to bear the possibility of this disease in mind when making a diagnosis.
