Urethral malignant melanoma closely mimicking urothelial carcinoma

Melanoma of the female urethra

Melanoma is a malignant tumor that can affect any area of the anatomical economy. Its appearance in the female urethra is extremely rare, with approximately 121 cases in indexed literature since 1966. The subject to be described is an 86-year-old woman who seeks assessment for intermittent macroscopic hematuria with blood clots of 3 months progression. On physical examination, there are no suspicious lesions detected on the surface of the skin. On external genital examination, it is observed a friable lesion at the level of the urethral meatus, with heterogeneous digitations, dark brown to black, and irregular polycyclic borders. No inguinal adenomegalies were palpated. Cystourethroscopy and biopsy of the lesion confirm the diagnosis. Melanoma of the female urethra is an extremely infrequent pathology. Due to lack of published case reports and the absence of prospective randomized trials on treatment outcomes, treatment must be directed using the same anatomical and surgical criteria for female urethral tumors, adding also the concepts of treatment of mucosal melanoma, even though its prognosis is different from the before mentioned.

Primary malignant melanoma of the urethra

Primary malignant melanoma of the urethra is an aggressive neoplasm associated with a poor prognosis. The outcome is dependent on early diagnosis and surgical intervention. However, the diagnosis is often delayed as a result of difficulties related to differentiating this lesion from other disorders. Such difficulties result from the variety of clinical and pathologic presentations that are common to melanoma. We report a case of primary malignant melanoma of the urethra with subsequent retrograde seeding of the bladder initially diagnosed and managed as invasive urothelial carcinoma.

Surgical technique for the conservative management of distal urethral melanoma

Urethral melanoma is very rare and pathological diagnosis is important. The prognosis remains poor irrespective of the treatment modality. Rare cases of long-term survival have been reported, one of them following conservative management. An initial attempt at conservative resection is worth considering to offer a better quality of life to the patient for as long as possible. We describe a technique of organ-sparing resection in the management of urethral melanoma along with the follow-up protocol that we adapted.

Primary malignant melanoma of the male urethra

BACKGROUND

We describe a rare case of malignant melanoma originating from the male urethra.

METHODS/RESULTS

This case, which presented a tan-colored lesion at the distal urethra on urethroscopy, was considered as transitional cell carcinoma by transurethral biopsy. Pathologic examination of widely resected urethra revealed scattering cells, which included melanin granules in cytoplasm, and then immunohistochemical stains established the diagnosis as amelanotic melanoma. Although partial penectomy and inguinal lymph node dissection were subsequently performed, 7 months later, total cystourethrectomy was required because of multifocal recurrence at the residual urethra.

CONCLUSIONS

In cases of amelanotic melanoma, it should be noted that a lack of melanin granules in tumor cells may lead pathologists and urologists to a misdiagnosis due to the histologic non-specific appearance. With respect to surgical management, of significance is the fact that malignant melanoma may progress multifocally along the total urethra; therefore, total urethrectomy should be considered as radical surgery for the primary site, even if the tumor is confined to the distal urethra.

Primary malignant melanoma of the urethra: a clinicopathologic analysis of 15 cases

The clinical and pathologic features of 15 primary urethral melanomas occurring in patients (nine women and six men) age 44 to 96 years (mean age, 73 yrs) are described. In the men the tumor involved the distal urethra. In eight women it involved the distal urethra, usually the meatus; both the distal and proximal urethra were involved in one woman. The tumors were typically polypoid and ranged from 0.8 to 6 cm (mean, 2.6 cm) in maximum dimension. A vertical growth phase was present in all tumors, with a prominent nodular component in seven of them. A radial growth phase was seen in nine tumors. The depth of invasion ranged from 2 to 17 mm. The tumors had diffuse, nested, storiform, or mixed growth patterns. The neoplastic cells typically had abundant eosinophilic cytoplasm, large nuclei with prominent nucleoli, and brisk mitotic activity. Melanin pigment was seen in 12 tumors but was conspicuous in only six. At the time of diagnosis, 13 tumors were confined to the urethra and two patients had lymph node metastasis. Nine patients died of disease 13 to 56 months after initial diagnosis and treatment, and one patient had a local recurrence at 4 years and subsequently died of sepsis 1 year later. Three patients were alive and well at 11 months, 23 months, and 7 years. One patient died at the time of the initial operation, and one died of a ruptured aortic aneurysm at 3 years without evidence of melanoma at autopsy. Primary malignant melanomas of the urethra, one fifth of which are amelanotic, must be included in the differential diagnosis of a number of primary neoplasms that involve the urethra, including transitional cell carcinoma, sarcomatoid carcinoma, and sarcomas. Conventional prognostic factors, such as depth of invasion or tumor stage, do not seem to play as important a role in predicting survival as the mucosal location and the nodular growth present frequently in these tumors.