Background:
The occurrence of calcitonin-secreting primary carcinoid tumor of the urinary bladder is extremely rare.
Case presentation:
The case of a 68-year-old male with carcinoid tumor arising in the urinary bladder is presented. Transurethral resection of a polypoid small tumor 0.4 cm in diameter was performed. Immunohistochemical study using neuroendocrine markers allowed a straightforward diagnosis of a low-grade neuroendocrine carcinoma (carcinoid tumor) of the urinary bladder. Immunohistochemistry demonstrated calcitonin immunoreactivity in the most of the tumor cells.
Conclusion:
This tumor shows specific clinical, macroscopical and histological features and must be considered in the differential diagnosis of bladder neoplasms.