# Gross hematuria in an immunocompromised male - A case report

## TL;DR

A rare case of Merkel cell carcinoma metastasizing to the bladder in an immunocompromised Hispanic male is reported, highlighting the use of narrowband imaging for diagnosis.

## Contribution

This is the first reported case of MCC bladder metastasis in a Puerto Rican immunocompromised male and the first to use narrowband imaging for MCC bladder diagnosis.

## Key findings

- MCC metastasis to the bladder is exceedingly rare and presents unique diagnostic challenges.
- Narrowband imaging was used for the first time in MCC bladder metastasis diagnosis.
- The case underscores the importance of considering rare metastatic sites in MCC patients.

## Abstract

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer with a high propensity for metastasis. While MCC has been reported in various organs, its metastasis to the bladder is exceedingly uncommon. Bladder infiltration in MCC presents a unique diagnostic and therapeutic challenge in Urology. Only few have been described worldwide, and no cases have been reported in Hispanic males. This is the first published case of an immunocompromised Hispanic patient with MCC metastasis to the bladder and to our knowledge, the first case report worldwide to include narrowband imaging (NBI) in the diagnostic algorithm of MCC to the bladder.

We report the case of a 53-year-old immunocompromised Puerto Rican male diagnosed with metastatic MCC. The patient had previously developed MCC with metastasis to the inguinal lymph nodes and received treatment. Later management involved immunotherapy once node persistence was found. Recent investigation revealed a new metastasis to the urinary bladder, presenting with gross hematuria. Diagnostic evaluation included computed tomography (CT) and Cystoscopy with white light and NBI, which confirmed the bladder metastasis. The patient underwent transurethral resection of the bladder tumor (TURBT) for tissue diagnosis. This work has been reported in line with the SCARE criteria (Sohrabi et al., 2023).

Histopathological analysis confirmed the diagnosis of metastatic MCC to the urinary bladder. The patient was managed with nephrostomy tube placement for obstructive uropathy and further immunotherapy for metastatic disease. Despite intervention, the prognosis remains poor due to the aggressive nature of the tumor and the patient's immunocompromised state.

This case highlights the unusual presentation of MCC with bladder metastasis in an immunocompromised Hispanic male. The patient revealed aggressive pathology per CT and developed persistent hematuria which were managed with bilateral nephrostomy for symptom relief. To our knowledge, this is the first reported case of MCC bladder metastasis in a Puerto Rican immunocompromised male, underscoring the importance of considering rare metastatic sites in MCC and tailoring treatment approaches accordingly.

•Merkel cell carcinoma is of neuroendocrine origin.•This malignancy is associated with suppression of the immune system.•Metastasis of this Merkel cell carcinoma to the urinary bladder is rarely documented in medical literature.•This is the first recorded case of a Puerto Rican with this metastasis.•This is the first time that narrow band imaging technique is used for identifying this malignancy.

Merkel cell carcinoma is of neuroendocrine origin.

This malignancy is associated with suppression of the immune system.

Metastasis of this Merkel cell carcinoma to the urinary bladder is rarely documented in medical literature.

This is the first recorded case of a Puerto Rican with this metastasis.

This is the first time that narrow band imaging technique is used for identifying this malignancy.