PRIMARY, PURE, LARGE-CELL NEUROENDOCRINE CARCINOMA OF THE URINARY-BLADDER

We report what to our knowledge is the first case in the English-langu age literature of a primary, pure, undifferentiated large-cell neuroen docrine carcinoma of the urinary bladder. To date, only one case of a large-cell neuroendocrine carcinoma was reported, and it was associate d with an adenocarcinoma most likely of urachal origin. On the other h and, slightly more than 100 cases of undifferentiated small-cell carci noma of the urinary bladder were reported, approximately one-half of w hich were associated with poorly differentiated transitional-cell carc inoma of the conventional type. The patient in our case was a 73-year- old man with a history of prostatic cancer treated with radiation ther apy. He presented with hematuria, leading to the discovery of a solita ry tumor on the dorsal wall of the urinary bladder. A diagnosis of lar ge-cell neuroendocrine carcinoma was made, supported by immunohistoche mical reactivity for chromogranin, neuron-specific enolase, and synapt ophysin; a variety of other hormonal markers of neuroendocrine tumors were negative. The radical cystoprostatectomy and bilateral pelvic lym phadenectomy specimen showed a transmurally invasive tumor, without re gional lymph node metastases, The patient died 2 months after surgery, and the autopsy revealed disseminated metastases histologically ident ical to the urinary bladder neoplasm, Awareness of the occurrence of l arge-cell neuroendocrine carcinoma of the urinary bladder seems to be important because of the possible aggressive outcome associated with t his tumor and because of differential diagnostic considerations, which include malignant lymphoma and metastasis from another primary, espec ially in tumors occurring in a pure form.