Neuroendocrine carcinoma of the urinary bladder: case report and review of the literature.

A 63-year-old Japanese man complained of hematuria and pollakisuria for several months. Computed tomography and cystography disclosed an infiltrative tumor mass in the irregularly thickened apical and posterior walls of the urinary bladder. Narrowing of the vesical lumen and posterior extension of the tumor into the pelvic cavity were also noted. After palliative ureterocutaneostomy, 60 Gy irradiation was given locally. The patient died of cachexia seven months later. Autopsy revealed neuroendocrine carcinoma of the urinary bladder with extensive invasions and metastases to the pelvic and peritoneal cavities, liver, lungs, vertebrae, left kidney and retroperitoneal lymph nodes. Histologically, atypical tumor cells with eosinophilic cytoplasm formed solid nests and anastomosing cords with pseudoglandular structures. No other histologic tumor components were included. An intact urachal remnant was found at the vesical apex while features of metaplastic cystitis were absent. In addition to positive carcinoembryonic antigen and cytokeratin, the argyrophilic cancer cells were immunoreactive for neuron-specific enolase, chromogranin A, serotonin, neuropeptide Y, glicentin, somatostatin, neurotensin and calcitonin. Ultrastructurally, neurosecretory-type granules, with a mean diameter of 166 nm, were identified in the cytoplasm of the tumor cells. To discuss the histogenesis of the tumor, 44 previously reported cases of neuroendocrine carcinoma of the urinary bladder were reviewed.