The different faces of mycosis fungoides: results of a single‐center study

Decoding Early Mycosis Fungoides: Histopathologic and Immunohistochemical Clues

INTRODUCTION

Primary cutaneous lymphomas, notably mycosis fungoides (MF), present diagnostic challenges in recognizing early mycosis fungoides (eMF) due to their diverse clinical and histopathologic manifestations. The aim of our study was to use adjunctive histopathologic and immunohistochemical methods in eMF cases to make an early diagnosis and to facilitate differentiation from other dermatoses.

METHODS

This retrospective study analyzed 35 cases of eMF diagnosed at a single center. Demographic and clinicopathologic data were collected, and histopathologic features were assessed. Comparative analyses were conducted with conditions mimicking eMF, including large plaque parapsoriasis (LPP), psoriasis, and chronic dermatitis. Immunohistochemistry for T-cell markers (CD3, CD4, CD8, CD2, CD7) was performed.

RESULTS

With the scoring we applied in our study, a sensitivity of 91.43% (95% CI; 76.94% to 98.20%) and specificity of 85.71% (95% CI; 69.74% to 95.19%) for distinguishing eMF from LPP. Epidermotropism emerged as a crucial histopathologic marker, with a notable absence in most cases of cutaneous dermatitis (81.6% and 80% for CD and psoriasis, respectively) (P < 0.001). Immunohistochemistry revealed a T-helper phenotype (CD4+/CD8-) in the majority of eMF cases (78.1%), while CD4+/CD8+ and CD8+/CD4- patterns were less common (28.5% and 8.5%, respectively).

CONCLUSION

This study underscores the complexities in distinguishing eMF from inflammatory skin diseases, advocating for a comprehensive diagnostic approach.

A Comprehensive Update of the Atypical, Rare and Mimicking Presentations of Mycosis Fungoides

Introduction

Mycosis fungoides (MF) is the most frequent subtype of primary cutaneous T cell lymphomas (pCTCL). The diagnosis may be particularly difficult in the early stages as well as in atypical and rare clinical presentations. Furthermore, MF may simulate a large variety of common dermatologic disorders and patterns, both histopathologically and clinically.

Methods

A literature search was performed to provide a comprehensive update on the rare and atypical MF manifestations as well as the dermatoses and dermatological patterns that could be imitated by MF.

Results

A total of 114 publications were found describing a series of different dermatoses and dermatological patterns mimicked by MF, as well as some particular localizations of MF lesions and dermatoses that occur in preexisting MF lesions.

Conclusions

The number of dermatoses that can be imitated by MF is ever-increasing. Patients with common dermatologic conditions that prove to be treatment refractory should be biopsied without delay, and sequentially as necessary, to prevent delay in diagnosis and progression of disease. Clinicopathologic correlation is the best way of diagnosis.

Single-cell RNA sequencing reveals markers of disease progression in primary cutaneous T-cell lymphoma

Background

In early-stage mycosis fungoides (MF), the most common primary cutaneous T-cell lymphoma, limited skin involvement with patches and plaques is associated with a favorable prognosis. Nevertheless, approximately 20–30% of cases progress to tumors or erythroderma, resulting in poor outcome. At present, factors contributing to this switch from indolent to aggressive disease are only insufficiently understood.

Methods

In patients with advanced-stage MF, we compared patches with longstanding history to newly developed plaques and tumors by using single-cell RNA sequencing, and compared results with early-stage MF as well as nonlesional MF and healthy control skin.

Results

Despite considerable inter-individual variability, lesion progression was uniformly associated with downregulation of the tissue residency markers CXCR4 and CD69, the heat shock protein HSPA1A, the tumor suppressors and immunoregulatory mediators ZFP36 and TXNIP, and the interleukin 7 receptor (IL7R) within the malignant clone, but not in benign T cells. This phenomenon was not only found in conventional TCR-αβ MF, but also in a case of TCR-γδ MF, suggesting a common mechanism across MF subtypes. Conversely, malignant cells in clinically unaffected skin from MF patients showed upregulation of these markers.

Conclusions

Our data reveal a specific panel of biomarkers that might be used for monitoring MF disease progression. Altered expression of these genes may underlie the switch in clinical phenotype observed in advanced-stage MF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-021-01419-2.

Clinical characteristics and long-term outcome of 223 patients with mycosis fungoides at a single tertiary center in Korea: A 29-year review

BACKGROUND

Data regarding Asian patients with mycosis fungoides (MF) are limited.

OBJECTIVE

We aimed to investigate the clinical profile and long-term outcomes of patients with MF in Korea.

METHODS

A retrospective review of 223 patients with MF who were followed up for more than 6 months or died of MF within 6 months of diagnosis was performed.

RESULTS

Approximately 96.4% and 3.6% of the patients had an early stage and advanced stage, respectively. The mean age at diagnosis was 44.8 years. The mean duration of symptoms before diagnosis was 47.0 months. Various subtypes were noted, including mycosis fungoides palmaris et plantaris (21.5%), folliculotropic (8.5%), pityriasis lichenoides-like (6.7%), ichthyosiform (4.0%), lichenoid purpura-like (2.7%), and hypopigmented (2.2%) MF. Juvenile patients accounted for 16.6%. The higher the skin T stage, the poorer the response to treatment. The 10-year overall survival was 96.8% in early-stage patients and 25.0% in advanced-stage patients. General prognosis was favorable, while recurrence and subtype switching were seen in 29.4% and 2.7% of patients, respectively.

LIMITATIONS

Our patients may not represent all Korean patients with MF.

CONCLUSION

MF in Korea has a high proportion of variants, a younger age at onset, and favorable prognosis. A high index of suspicion and skin biopsy are needed for early diagnosis.