[Cutaneous lymphomas: new entities and rare variants]

Area of Science:

• Dermatology
• Hematology
• Oncology

Context:

• Primary cutaneous lymphomas represent the second most frequent extranodal non-Hodgkin lymphomas.
• Recent discoveries include new variants and entities not yet incorporated into the World Health Organization classification.
• These include granulomatous mycosis fungoides, indolent CD8+ lymphoproliferations, and novel lymphomatoid papulosis subtypes.

Purpose:

• To review the clinical, histological, and immunophenotypic characteristics of newly identified and rare cutaneous lymphoma entities.
• To emphasize the importance of clinicopathological correlation in diagnosing these challenging cases.
• To discuss the evolving landscape of cutaneous lymphoma classification.

Summary:

• The review covers new variants of cutaneous lymphomas, such as granulomatous mycosis fungoides and indolent CD8+ lymphoproliferations.
• It details new histological types of lymphomatoid papulosis (types D and E) and aggressive T-cell lymphomas (cutaneous CD8+ epidermotropic cytotoxic T-cell lymphoma, cutaneous gamma/delta T-cell lymphoma).
• Epstein-Barr virus-associated B-cell lymphomas, including diffuse large B-cell lymphoma of the elderly and EBV-associated mucocutaneous ulcer, are also discussed.

Impact:

• Accurate diagnosis of these rare entities is critical due to their varied prognoses.
• Understanding new variants aids in refining the World Health Organization classification of cutaneous lymphomas.
• Improved clinicopathological correlation enhances diagnostic accuracy and patient management strategies.