Mycosis Fungoides and Granulomatous Slack Skin: A Single Entity With Distinct Clinical Phenotypes

Area of Science:

• Dermatopathology
• Oncology
• Cutaneous Lymphoma Research

Background:

• Granulomatous cutaneous T-cell lymphoma encompasses granulomatous mycosis fungoides (GMF) and granulomatous slack skin (GSS), both WHO-classified subtypes of mycosis fungoides.
• These conditions share clinical and histopathologic features, posing diagnostic challenges due to prominent granulomatous infiltrates and sparse atypical lymphocytes.

Purpose of the Study:

• To describe the clinical and histopathologic characteristics of three granulomatous cutaneous T-cell lymphoma cases.
• To illustrate the relationship between GMF and GSS and highlight diagnostic difficulties.
• To investigate elastolysis in classical mycosis fungoides.

Main Methods:

• Case series analysis of clinical and histopathologic findings.
• Histopathological examination focusing on inflammatory infiltrates and elastolysis.
• Comparison of features between GMF, GSS, and classical mycosis fungoides.

Main Results:

• Demonstrated overlapping features between GMF and GSS, suggesting a close relationship.
• Highlighted how granulomatous inflammation can obscure diagnosis in cutaneous T-cell lymphoma.
• Observed significant elastolysis in classical mycosis fungoides lesions, previously unreported.

Conclusions:

• GMF and GSS may not be distinct entities but rather represent variations in degree and location of a single process.
• Elastolysis is a feature present in classical mycosis fungoides, further blurring the lines between these conditions.
• Diagnostic challenges in granulomatous cutaneous T-cell lymphoma necessitate careful evaluation of both inflammatory and neoplastic components.