Primary malignant urethral melanoma resembling a urethral caruncle

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.

Role of 18 F-FDG PET-CT in Urethral Malignant Melanoma and Analysis of the UK Guidelines on Ano-uro-genital Melanomas

Urethral melanomas are a rare subtype of noncutaneous melanomas. The disease has a tendency to have skip lesions and early metastases as compared with cutaneous melanomas. The role of fluorine-18 fluorodeoxyglucose ( 18 F-FDG) positron emission tomography computed tomography (PET-CT) is well established in cases of cutaneous melanomas and is recommended by the National Comprehensive Cancer Network (NCCN) for stage IIB to IV cancer. There are no established guidelines on the management of noncutaneous melanomas; however, a recently published United Kingdom national guideline aims to streamline the management of ano-uro-genital melanomas. The guideline describes a very limited role in the use of 18 F-FDG PET-CT in this case scenario. The tendency to skip lesions, early metastases, involvement of brain parenchyma, and finally the usage of anti-PD-1 medications are key areas where 18 F-FDG PET-CT has shown superiority over CT scan. With this case report, we aim to highlight the strength of 18 F-FDG PET-CT in the management of urethral melanomas, which can be extrapolated to other ano-uro-genital melanomas.

Primary Malignant Melanoma of the Genitourinary System: A Systemic Review and Report of Eight Cases

Malignant melanoma (MM) of mucosal membranes (excluding anus and head-neck) is a rare but aggressive disease with poor outcomes. The knowledge of this tumor's development, etiology, and management is scarce, mainly due to the low case numbers. We presented eight cases and performed a comprehensive literature review on mucosal MM (between 1970 and 2020). We identified 47 manuscripts on 55 patients with primary mucosal MM (limited to urothelium and vagina) and reviewed demographics, tumor specifications (morphology, stage, etc.), management, and survival. We identified 10 manuscripts discussing treatment in 1595 mucosal and non-mucosal MM and extracted the data regarding the non-surgical treatment modalities of mucosal MM patients. In 63 cases, 48 tumors primarily occurred in the urothelium (urethra: 47, bladder: 1) and 15 in the vagina. Molecular studies in a subset of cases revealed alterations in c-KIT, NRAS, BRAF (non-V600E and V600E), TP53, and NF1. Fifty-three patients underwent surgery (with additional chemotherapy, immunotherapy, and radiotherapy in 19, eight, and eight patients, respectively). The outcome was available in 52 cases, showing 21 deaths, 10 without recurrence, two alive with disease, and five lost to follow-up. Shared genetic signatures in mucosal and skin MM suggest a similar development mechanism; however, unlike skin MM, there are less BRAF mutations and more PI3K/AKT/mTOR pathway alterations in mucosal MM. Prolonged chemotherapy (i.e., methotrexate) and immune-modulating agents (i.e., natalizumab) may be risk factors. The stage at diagnosis and proper surgical extirpation are keys to the prognosis and survival of patients.

Urethral Caruncle Masquerading a Primary Amelanotic Melanoma, the Risk of a Poor Prognosis due to Misdiagnosis

Objective: Primary malignant urethral melanoma is a rare condition, concerning less than 1% of melanomas and 4% of all urethral cancers. The early treatment of urethral melanoma is extremely important due to the tendency to early metastasis. Case report : 88-year-old Caucasian lady presented vaginal bleeding. At first Gynaecological examination an urethral caruncle with otherwise normal trans-vaginal ultrasound was diagnosed. The patient not reassured asked for a second consultation opting to remove the reddish fleshy polypoid lesion protruding from the urethra. Histology revealed a urethral amelanotic melanoma. The patient underwent an excission of the urethral lesion. Urologist, oncologist and gynaecologist at tumor board meeting, considering patient's age and negative PET, decided for conservative management with close clinical and imaging follow-up.7 months after, vaginal bleeding recurred and a nodule on the anterior vaginal wall was detected and biopsied and resulted a pigmented melanoma. The patient underwent a wide margin excision. At 10 months follow-up there were no evidence of recurrence nor distant metastasis. She started a prophylactic immunotherapy with Nivolumab; at her third administration she presented only asthenia as side effect. Conclusion: It is importanto to keep in mind the urethral amelanotic melanoma to allow an early removal or biopsy, preventing diagnostic delay/misdiagnosis and aiding either in better patient management or outcome.

Carbon ion radiotherapy with complete tumor regression for primary malignant melanoma of female urethra orifice: a case report

Primary malignant melanoma of the female urethra (PMMFU) is extremely rare, accounting for 0.2% of all melanomas, and fewer than 200 cases have been reported worldwide. Because of the small number of clinical cases and unclear biological characteristics, there is no uniform and standard treatment protocol. We herein describe the treatment of PMMFU using carbon ion radiotherapy. The radiotherapy was delivered at 60.8 Gy (RBE) in 16 fractions, once daily, five times per week. The patient achieved complete tumor disappearance within 1 year after carbon ion radiotherapy and remained disease-free thereafter. She developed acute grade 1 radiation dermatitis and urethritis, which resolved quickly; no other toxic effects were observed. At the time of this writing, her survival duration was 33 months. This case demonstrates that carbon ion radiotherapy may be a good option for primary genitourinary mucosal malignancies.

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.

Urethral bulking agent found in a urethral caruncle which did not respond to topical oestrogens: A case report

Background

Urethral caruncles are lesions occurring at the urethral orifice, around the posterior lip of the urethra. They are the most common benign growth of the female urethra. They are often asymptomatic and found incidentally on clinical examination. When symptomatic they commonly present with bleeding. Treatment includes vaginal oestrogens or, failing that, surgical excision. We present an unusual finding after excision of a urethral caruncle.

Case

A patient with a background of stress urinary incontinence had numerous pelvic surgeries, including colposuspension, tension-free vaginal tape (TVT) and Macroplastique (a urethral bulking agent). She developed bleeding from a 3 cm urethral caruncle, which did not improve with vaginal oestrogens. She proceeded to have a surgical excision of the caruncle. Histology revealed a foreign material with surrounding foreign-body-type multinucleate giant cell reaction. The material was compatible with Macroplastique.

Conclusion

This case report describes an unusual and unexpected histological finding. Macroplastique is injected in the urethra, 10–15 mm from the bladder neck. We suspect the caruncle dragged the Macroplastique material out through the urethral meatus. If urethral caruncles are not adequately treated with vaginal oestrogens, surgery should be considered.

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Urethral caruncles are lesions occurring at the urethral orifice, around the posterior lip of the urethra

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They are the most common benign growths of the female urethra

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When symptomatic they commonly present with bleeding.

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Treatment includes topical oestrogens or failing that, surgical excision.

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The presence of a urethral bulking agent in a caruncle, which did not respond to topical oestrogen, is reported.

Urinary tract bleeding from a urethral caruncle mimicking genital tract bleeding

A 69-year-old Japanese woman with a post-hysterectomy status came to our primary care clinic. She presented with vaginal bleeding for the past 3 days which had developed after defecation. There was a palpable mass measuring approximately 2 cm on pelvic exam; however, heavy bleeding prevented in-depth observation. CT and MRI scans revealed that the mass was inside the urethral meatus and not in the vagina. She underwent surgical resection of the urethral tumour, and the pathological report showed no malignancy. A final diagnosis of urethral caruncle was made. Vaginal bleeding is commonly encountered in the primary care practice and is usually attributed to gynaecological diseases. However, patients and physicians may falsely regard urinary or gastrointestinal tract bleeding as one involving the genital tract. We present a case wherein vaginal bleeding was initially considered but was later identified to be due to a urethral caruncle.

"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.