A Rare Case of Primary Malignant Melanoma of the Bladder

Bladder melanoma is an extremely rare malignant tumor originating from melanocytes, the cells that produce melanin. Accounting for less than 0.2% of all melanomas, with approximately 30–50 cases reported in the medical literature so far. A case by Wheelock M.C. in 1942 is commonly cited as the first reported case.

In early October, a case report was published describing a 71-year-old woman with primary bladder melanoma. The case report is titled ‘Primary Malignant Melanoma of the Bladder: A Rare Case Report.’ The authors are Huber Díaz-Fuentes, Seiichi Fuziwara-Ruíz, Eduardo de los Santos-Frias, Eduardo Amaya-Fragoso, Eduardo Rodríguez-Araujo, Eduardo Ramos-Arceo, Luis Aguirre-Amador, and Cristopher Hernández-Rodríguez.

“Early diagnosis is challenging, and patients usually present with gross hematuria and dysuria. Here, we present a case of primary bladder melanoma, describing the clinical, morphological, and immunohistochemical findings,” the authors wrote.

Case report

The authors described a case of a 71-year-old woman who presented with frequent urination, dysuria, a sensation of a foreign body in the vagina, and macroscopic hematuria. Ultrasound of the kidneys and bladder revealed an intra-bladder lesion measuring approximately 8 cm, and histopathological examination confirmed the diagnosis of malignant melanoma. Given the highly aggressive nature of primary bladder melanoma, its tendency for early metastasis, and poor overall prognosis, the multidisciplinary team recommended definitive surgical treatment.

Lessons for clinicians

The authors conclude that this case highlights several important lessons for clinicians: primary malignant melanoma of the bladder may present with unusual features, such as a pigmented mass in the urethra, emphasizing the need for thorough evaluation of pigmented lesions in the urinary tract. They pointed out that the report emphasizes the critical importance of considering melanoma in the differential diagnosis of pigmented bladder lesions.

Reporting rare cases is extremely important

Reporting rare cases, such as primary malignant melanoma of the bladder, is of great importance to both the medical community and the general public. Since the disease often presents with nonspecific symptoms, reporting these cases not only contributes to the research community and improves understanding of the disease, but also educates people about the importance of monitoring their own symptoms and seeking professional help when changes occur in their urinary tract health.

Image: MRI showing the lesion/Study