Primary melanoma of the male urethra

Melanoma of glans penis and urethra: A case report and systematic review of the literature of a rare and complex neoplasm

OBJECTIVE

To evaluate the features and prognosis of melanoma of glans penis and urethra, with the presentation of a significant case report.

MATERIALS AND METHODS

A systematic literature review was performed using the MEDLINE (PubMed) and Cochrane Libraries databases to identify all cases of male mucosal melanoma reported.

RESULTS

Two hundred fifty-two patients with male mucosal primary melanoma were found. Glans penis and fossa navicularis as primary site includes the 81.6% of all lesions considered. Median Breslow's depth is 2.1 mm, whereas nine in situ melanomas have been reported. At the diagnosis, the disease was at a non-localized stage in 21.4% for glans penis melanomas and 11.7% urethral lesions, respectively. The 2 and 5-year survival for glans melanoma is 62.5% and 38.4%; higher rates were observed in the 2012-2020 period (76% and 58.8%, respectively). Two-year survival for urethral melanomas is 66.7%, while 5-year survival is 12.5%. 22 patients survived over 5 years with a Breslow's depth reported always < 3.3 mm.

CONCLUSION

Melanoma of the glans penis and urethra is a rare neoplasm associated with a poor prognosis, however recent reports show higher survival rates. Surgery remains the mainstay for a localized disease. Taking into account the small number of cases reported, topical imiquimod seems to be a valid non-surgical alterative for melanoma in situ. The use of immunotherapy and targeted therapy should be considered only in an adjuvant setting according to the recommendations of cutaneous melanoma; however, additional clinical data on male mucosal melanoma are needed to draw definitive conclusions.

Identification of distinct genomic features reveals frequent somatic AHNAK and PTEN mutations predominantly in primary malignant melanoma presenting in the ureter

BACKGROUND

Primary malignant melanoma of the ureter is extremely rare. Genetic variants to the increased risk of developing the disease have not yet been investigated.

METHODS

Tumour mutation profiling for primary malignant melanoma of the ureter was performed by whole-exome sequencing. Immunohistochemistry was performed to verify histopathological features and the variants of predisposing genes and driver mutation genes. Furthermore, we conducted a literature review and Surveillance, Epidemiology and End Result-based study by searching public databases.

RESULTS

We identified 38 somatic single nucleotide variants and 9 somatic insertions and deletions (INDELs) in tumour specimens. After filtering with the Cancer Gene Census database, seven predisposing genes and two driver mutation genes were identified. Moreover, the immunohistochemical profile showed that tumour cells were positive for Melan-A, melanoma gp100 human melanoma black 45 (HMB45), S100 beta and P53. The expression levels of two driver mutation genes (phosphatase and tensin homolog (PTEN) and desmoyokin (AHNAK) and five predisposing genes (AT-rich interaction domain 1B (ARID1B), catalase, eukaryotic translation initiation factor 4 gamma 3 (EIF4G3), ANK3 and collagen type I) were significantly downregulated in tumour tissues compared to paracancerous tissues. In the literature review and Surveillance, Epidemiology and End Results-based study, patients with primary malignant melanoma of the urinary tract had worse clinical outcomes than patients with primary urothelial carcinoma after 1:2 propensity score matching (P = 0.010). Additionally, Cox multivariate analysis for patients with primary malignant melanoma of the urinary tract indicated that distant metastasis (hazard ratio = 1.185; P = 0.044) was an independent predictor for overall survival, and tumour focality (hazard ratio = 0.602; P = 0.017) and non-surgery (hazard ratio = 0.434; P = 0.003) were independent factors for tumour progression.

CONCLUSIONS

Our study is the first to provide evidence that the distinct phenotypes of primary malignant melanoma of the ureter may be due to different genetic variations. The prognosis of primary malignant melanoma of the urinary tract was poorer than that of primary urothelial carcinoma of the urinary tract.

Urological Melanoma: A Comprehensive Review of a Rare Subclass of Mucosal Melanoma with Emphasis on Differential Diagnosis and Therapeutic Approaches

Melanoma is reported as the 19th most common cancer worldwide, with estimated age-standardized incidence rates of 2.8-3.1 per 100,000. Although the origin is most frequently cutaneous, mucosal melanoma has been described several times in literature, and despite its rarity (only 1% of all melanomas), increasing attention is being paid to this disease form. Within this subgroup, melanomas of the uropoetic apparatus are a rarity among rarities. Indeed, less than 50 cases of primary melanoma originating from the urinary bladder have been described, and even less originating from the kidney, renal pelvis and urethra. In this work, we present a detailed review of the literature related to this subclass of mucosal melanoma, delve into the biological landscape of this neoplasm and discuss current approaches, future perspectives and potential therapeutic approaches.

"Man in Istanbul" Lesions of the Urinary Tract (Known Entities in an Unusual Context): Melanoma, Carcinoid Tumors, Epithelioid Angiosarcoma

Certain tumors are more difficult to recognize when they present in an unusual location. Within the urinary tract, primary melanomas, carcinoid tumors, or epithelioid angiosarcoma could present diagnostic challenges due to their infrequent occurrence. This article emphasizes the clinical and histopathologic features of these entities and their differential diagnoses including the immunophenotype and their prognoses.