Mucosal Melanoma

Mucosal melanoma is a rare and aggressive form of melanoma that arises from the mucous membranes of the body, including the nasal passages, oral cavity, genital tract, and anorectal region. Distinct from the more common cutaneous melanoma, mucosal melanoma presents unique challenges in diagnosis and treatment due to its location and often late-stage detection. 

Unlike cutaneous melanoma, which is related to UV exposure, mucosal melanoma's aetiology is not well understood. The malignancy originates from melanocytes located within the mucosal lining, which are less visible and challenging to monitor.

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Symptoms of Mucosal Melanoma

Nasal and Sinus Melanoma Symptoms

Mucosal melanoma in the nasal passages and sinuses may manifest as nasal obstruction, nosebleeds, or persistent sinus infections. Due to the non-specific nature of these symptoms, early detection is often difficult.

Oral Melanoma Symptoms

Oral mucosal melanoma can present as a pigmented lesion in the mouth, often on the palate or gums. Symptoms may include swelling, bleeding, and discomfort, though some lesions may be asymptomatic, delaying diagnosis.

Genital Tract Melanoma Symptoms

Mucosal melanoma of the genital tract can affect both men and women. It presents as pigmented lesions or masses. Symptoms may include bleeding, pain, or discharge, and it is often mistaken for less severe conditions.

Anorectal Melanoma Symptoms

Anorectal mucosal melanoma is particularly insidious, often presenting with rectal bleeding, pain, or a palpable mass. Symptoms may mimic those of haemorrhoids or other benign conditions, complicating early diagnosis.

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Causes of Mucosal Melanoma

The precise causes of mucosal melanoma remain largely unknown. Unlike skin melanoma, mucosal melanoma does not have a strong correlation with UV exposure. Genetic factors may play a role, and researchers are investigating potential links to certain viral infections or environmental influences. Understanding the risk factors associated with mucosal melanoma is crucial for developing preventive strategies.

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Diagnosis of Mucosal Melanoma

Clinical Examination and Imaging

The diagnosis of mucosal melanoma typically begins with a thorough clinical examination, often followed by imaging studies such as MRI or CT scans to assess the extent of the disease. These imaging modalities help visualize the tumour and determine its spread to adjacent tissues or distant organs.

Biopsy and Histopathological Analysis

A definitive diagnosis is achieved through biopsy and histopathological examination. The biopsy involves sampling the suspicious lesion, which is then analyzed under a microscope to confirm the presence of melanoma cells. Histological analysis also aids in determining the tumour's characteristics and potential behaviour.

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Treatment Options for Mucosal Melanoma

Surgical Intervention

Surgery is the primary treatment modality for localized mucosal melanoma. The goal is to achieve clear margins, which may require extensive resection depending on the tumour's location and size. Due to the challenging anatomical sites involved, surgical procedures can be complex and may require reconstruction.

Radiation Therapy

Radiation therapy is often employed as an adjunct to surgery, particularly in cases where complete surgical excision is difficult. It can also be used as a soothing treatment to relieve symptoms in advanced cases.

Systemic Therapies

Immunotherapy

Recent advancements in immunotherapy have shown promise in treating mucosal melanoma. Agents such as checkpoint inhibitors (e.g., pembrolizumab, nivolumab) enhance the body's immune response against melanoma cells, offering hope for improved outcomes in metastatic cases.

Targeted Therapy

Targeted therapies focus on specific genetic mutations within melanoma cells. While mucosal melanoma shares some genetic similarities with cutaneous melanoma, the efficacy of targeted agents remains an area of active research. Current therapies may include agents targeting c-KIT mutations, which are more prevalent in mucosal melanoma.

Clinical Trials

Given the rarity of mucosal melanoma, clinical trials play a critical role in exploring new treatment avenues. Patients with advanced disease may consider participating in trials investigating novel therapeutic approaches, including combination therapies and new drug classes.

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Prognosis and Management

Prognostic Factors

The prognosis for mucosal melanoma is generally poorer compared to cutaneous melanoma, largely due to its late-stage diagnosis and aggressive nature. Prognostic factors include tumour thickness, ulceration, and the presence of metastases at diagnosis.

Long-term Management

Long-term management of mucosal melanoma involves regular follow-up with a multidisciplinary team, including oncologists, surgeons, and radiologists. Surveillance strategies may include periodic imaging and clinical evaluations to monitor for recurrence or metastasis.