Re: Melanoma of the Penis, Scrotum and Male Urethra: A 40-Year Single Institution Experience

Exploring the landscape of urinary tract melanomas: A review for pathologists and clinicians

Melanomas originating within the urinary tract represent a rare and clinically challenging subset of malignancies. Despite extensive research on cutaneous melanomas, urinary tract melanomas remain relatively unexplored, presenting diagnostic dilemmas and limited treatment consensus. In this comprehensive review, we synthesize current knowledge on the epidemiology, risk factors, clinical presentation, histopathological characteristics, and treatment strategies specific to this disease. Enhancing clinical awareness, refining diagnostic approaches, and exploring novel therapeutic interventions hold promise for improving outcomes in this challenging malignancy subset.

Primary malignant melanoma of the male urethra: Case report and review of literature

INTRODUCTION

We report a rare case of primary malignant melanoma with inguinal lymph node metastasis in the male urethra.

CASE PRESENTATION

A 57-year-old male patient presented with a small tumor on the ventral surface of the penis, which was discovered 5 months ago and did not cause pain or discomfort. In the past month, the patient has developed symptoms of urinary incontinence. MRI and PET/CT scans revealed a primary tumor in the penile urethra, but no metastases were found. The patient underwent partial penectomy surgery and laparoscopic bilateral inguinal lymphadenectomy within one month. The pathological combined with immunohistochemical staining confirmed primary malignant melanoma in the urethra with right inguinal lymph node metastasis. Despite complying with surgical and immunotherapy treatment with Pembrolizumab for 18 cycles, the patient was diagnosed with recurrent cancer in the penile stump after 05 months and he passed away after 18 months.

DISCUSSION

Urethral melanoma is a rare and highly invasive type of cancer. It was often diagnosed at a late stage because the initial symptoms were not obvious in the lower urinary tract. Additionally, cancer progressed very quickly, making it difficult to treat.

CONCLUSION

Urethral melanoma, if detected at a late stage with lymph node metastasis, has a significantly poor prognosis irrespective of the treatment method employed. However, to our best knowledge, very few publications can be found on this disease, and the strategic treatment remained unknown.

A case report of primary malignant melanoma of male urethra with distinct appearance in multiple regions

A 66-year-old man presented with macrohematuria. Cystoscope examination found a 5 mm nodular tumor at external urethral orifice and multiple papillary tumors at fossa navicularis of urethra; those are non-black colored. Transurethral resection of the urethra tumor was performed, and pathologically diagnosed as malignant melanoma. Image examinations showed no lymphadenopathy and metastasis. Accordingly, total penectomy was conducted to remove the remaining tumors, resulting in surgically curative resection. After the operation, monthly interferon-β injection into inguinal region has been administered as adjuvant therapy, resulting in no recurrence at 6 months after penectomy.

Melanoma of the penis with scintigraphically-guided sentinel node biopsy

Melanoma of the penis is an uncommon cancer. We present the case of a 73-year-old male with penile melanoma and non palpable lymph nodes. Lymphoscintigraphy was applied to locate the sentinel lymph nodes for dissection. His lymph nodes were negative for melanoma and he has been disease-free for 1 year with careful surveillance.

Penile malignant melanoma in a hemodialysis patient

A patient who was receiving hemodialysis treatment developed melanotic macules on the surface of the penis in 2002 and showed a tumor-like mass in the same region in July 2006. The patient presented with a pedunculated tumor of 3 cm in diameter on the right side of his penis. The tumor was resected for biopsy and was diagnosed as malignant melanoma. The melanoma was in stage IIIB with pT4 N1 M0. The patient received interferon-beta for a total of three courses. A computed tomography scan in the 10th postoperative month did not find any additional metastatic foci or recurrence of the tumor. In the present case, side effects caused by interferon were not observed. Therefore, particularly in dialysis patients, immune therapy might be favored over anticancer drug treatment.

Extracutaneous malignant melanomas

Extracutaneous malignant melanomas are rare tumors with vexing clinical presentation and grim prognosis. Only 4%-5% of all primary melanomas do not arise from the skin. These tumors are almost uniformly fatal, even in 2006. Although a fairly good number of these lesions were reported in the literature, the lack of a side-by-side analysis of these studies has resulted in tentative conclusions that merely offer a first glimpse at the clinicopathologic diversity of these lesions. To remedy this issue, this article took an aim at presenting a literature review concerning extracutaneous malignant melanomas. It also reports several cases of extracutaneous melanomas, which I came across in my 15 years of surgical and molecular pathology practice. The study raises several notions. Extracutaneous malignant melanomas are rare but extremely aggressive lesions with a grim outcome. They include ocular, metastatic, anorectal, mucosal, nail beds, conjunctival, vaginal, urogenital, orbital, esophageal, and leptomeningial malignant melanomas. The development of these lesions lacks an association with sun damage, family history, or precursor nevi. These lesions cause considerable diagnostic consternation and their distinction from other types of tumors (such as undifferentiated carcinomas, high-grade sarcomas, and lymphomas) is critical both from a diagnostic and prognostic point of view. In the proper clinical, histological, and cytological context, immunopositivity for S100 protein, HMB45, and vimentin allows the distinction of these malignant melanomas from other histologically similar malignancies. To conclude, extracutaneous melanoma should be considered while undifferentiated neoplasms, especially those displaying prominent eosinophilic nucleoli, and the coexistence of epithelioid and spindle cells. Special staining and immunohistochemistry should be resorted to establish the diagnosis.