Gross hematuria in an immunocompromised male - A case report.

introduction and importanceMerkel 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. CASE PRESENTATION: 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). CLINICAL DISCUSSION: 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.

conclusionsThis 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.