# Unusual Association of Large Cell Neuroendocrine Carcinoma of the Bladder and Prostatic Adenocarcinoma Within a 76-Year-Old Man

## TL;DR

A 76-year-old man was diagnosed with two rare cancers: large cell neuroendocrine bladder cancer and prostatic adenocarcinoma, a previously unreported combination.

## Contribution

This is the first reported case of LCNEC of the bladder co-occurring with prostatic adenocarcinoma.

## Key findings

- The patient had LCNEC of the bladder confirmed by biopsy and muscle invasion.
- A second lesion in the prostate was identified and confirmed as prostatic adenocarcinoma.
- The case highlights the need for a codified treatment strategy for this rare tumor combination.

## Abstract

Large cell neuroendocrine carcinoma (LCNEC) is one of the rarest types of bladder cancer, with an aggressive course and a poor prognosis. We report a case of LCNEC of the bladder associated with a prostatic adenocarcinoma. A very rare association, to our knowledge, is described for the first time in the literature. The patient was a 76-year-old non-smoker male, who presented with intermittent hematuria and dysuria. Cystoscopy revealed a lesion on the right lateral bladder wall. Biopsy was in favor of a LCNEC with muscle invasion. The CT scan showed the presence of a second lesion in the prostate, confirmed by histological examination. The patient was treated by neoadjuvant chemotherapy of the cisplatin-etoposide type for large-cell bladder neuroendocrine carcinoma, and hormone therapy with luteinizing hormone-releasing hormone (LH-RH) analogs for prostatic adenocarcinoma, followed by radical surgery. Given the rarity of this tumor, LCNEC treatment lacks precision. Many cases are published with different therapeutic strategies. A literature review would be interesting to codify the therapeutic strategy for this rare tumor.