Uncommon Subtypes of Malignant Melanomas: A Review Based on Clinical and Molecular Perspectives

Area of Science:

• Oncology
• Dermatology
• Pathology

Background:

• Malignant melanoma is an aggressive skin cancer with improving prognoses due to targeted agents and immune checkpoint inhibitors.
• Current research predominantly focuses on common cutaneous melanoma (CM) subtypes, leaving rare melanomas understudied.
• A clear definition and understanding of rare melanoma subtypes are lacking.

Purpose of the Study:

• To review the clinical and molecular characteristics of rare melanoma subtypes.
• To explore current and emerging treatment strategies for these less common melanomas.
• To consolidate evidence on melanomas arising from non-traditional primary sites.

Main Methods:

• Literature review of clinical and molecular data on rare melanoma subtypes.
• Inclusion of uncommon CMs (e.g., those without V600E/K BRAF mutations), mucosal, uveal, amelanotic, desmoplastic, and spitzoid melanomas.
• Analysis of melanomas from non-traditional sites like meninges, lymph nodes, esophagus, and breasts.

Main Results:

• Rare melanomas encompass a diverse group, including those with distinct molecular profiles (e.g., rare BRAF mutations) and those from unusual locations.
• Treatment approaches for rare melanomas are evolving, often adapting strategies from common CMs but requiring specific considerations.
• Evidence for effective therapies in mucosal, uveal, and other rare subtypes is accumulating.

Conclusions:

• Rare melanomas present unique challenges in diagnosis and management.
• Further research into the molecular underpinnings and tailored treatments for rare melanoma subtypes is crucial.
• This review provides a foundation for understanding and managing these challenging conditions.