Primary cutaneous lymphoma: the 2018 update of the WHO-EORTC classification

The fifth edition of the WHO-Classification - what is new for cutaneous lymphomas?

The recently published 5th edition of the "World Health Organization classification of hematolymphoid tumors: lymphoid neoplasms" provides a hierarchical reorganization. In general, new (definitive) entities as well as tumor-like lesions were included. Primary cutaneous B-cell lymphomas (CBCL) received a thorough review. A new class/family of cutaneous follicle center lymphomas was defined. Primary cutaneous marginal zone lymphoma is now presented as a separate entity independent from extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. In primary cutaneous T-cell lymphoma, former provisional entities were upgraded to definite entities. Sézary Syndrome was sorted into the class/family of mature T-cell and NK-cell leukemias. Additionally, a newly formed entity of primary cutaneous peripheral T-cell lymphoma, NOS was created for CTCL entities that do not fit into the already described CTCL entities. The increasing importance of genomic and molecular data has already been recognized in classifying leukemias and systemic lymphomas. However, in PCL the genomic landscape has not yet been fully described and validated. Therefore, future research is necessary to describe the genomic and molecular mechanisms underlying the disease entities more clearly. This would both meet a diagnostic need and valuably contribute to future classification schemes.

RuBi-Ruxolitinib: A Photoreleasable Antitumor JAK Inhibitor

We describe the synthesis and biological testing of ruthenium-bipyridine ruxolitinib (RuBiRuxo), a photoreleasable form of ruxolitinib, a JAK inhibitor used as an antitumoral agent in cutaneous T-cell lymphomas (CTCL). This novel caged compound is synthesized efficiently, is stable in aqueous solution at room temperature, and is photoreleased rapidly by visible light. Irradiation of RuBiRuxo reduces cell proliferation and induces apoptosis in a light- and time-dependent manner in a CTCL cell line. This effect is specific and is mediated by a decreased phosphorylation of STAT proteins. Our results demonstrate the potential of ruthenium-based photocompounds and light-based therapeutic approaches for the potential treatment of cutaneous lymphomas and other pathologies.

Determination of T-cell clonality and expression profiles of Toll-like receptors signaling pathway genes and related miRNAs in patients with mycosis fungoides

Cutaneous T-cell lymphomas (CTCL) encompass a group of diseases characterized by the presence of malignant clonal CD4+ T lymphocytes in the skin. Mycosis fungoides (MF) is the most prevalent form of CTCL, accounting for approximately 60 % of cutaneous T-cell lymphomas and 50 % of all primary cutaneous lymphomas. Despite ongoing research, the precise pathogenesis of MF remains incompletely understood. Toll-like receptors (TLRs) have the ability to specifically recognize ligands, subsequently induce the expression of diverse genes and activate innate immunity within the cell. Furthermore, miRNAs play a crucial role in regulating various aspects of immune cell function. The aim of our study was to explore the potential roles of TLRs and the genes implicated in their signal transduction, along with the expression status of miRNAs in the mechanisms underlying MF. Additionally, we assessed the clonal status and compared it with clinicopathological data using a T-cell clonality assay. To determine the expression status of TLR pathway genes and miRNAs, we conducted RT-PCR analysis on 52 MF samples and 50 control paraffin block materials. Pathway analysis were conducted using the KEGG database. T-cell receptor (TCR) gamma clonality changes were evaluated. Results from the study revealed increased expressions of TLR-1, -4, -8, IRF7, TRAF3, MEK1, MEK2, Elk1, NFkB, hsa-miR-21-5p, and hsa-miR-155-5p, as well as decreased expressions of hsa-miR-130a-3p, hsa-miR-210-3p, and hsa-let-7e-5p in the MF group. TCR gamma clonal change analysis demonstrated that 55.5 % of the analysed DNAs exhibited monoclonal and biallelic patterns, while 45.5 % displayed polyclonality. These findings collectively suggest the potential influence and therapeutic possibilities of the TLR signalling pathway in the molecular pathogenesis of MF.

Dermatoscopic Characteristics, Lesional Capillaroscopic Features, and Histopathological Correlation of Small Plaque Parapsoriasis and Mycosis Fungoides

INTRODUCTION

Dermatoscopy is a frequently used non-invasive diagnostic procedure.

OBJECTIVES

Considering that mycosis fungoides (MF) mimics parapsoriasis clinically in early stages, we aim to determine the dermatoscopic criteria and the histopathological correlations in patients with MF and small plaque parapsoriasis (SPP).

METHODS

This prospective study involved 28 patients with clinical and histopathological diagnoses of MF and 31 patients with SPP. Videodermoscopy and USB capillaroscope were used to evaluate the patients vessels at ×200 magnification. Vascularity was evaluated through microvascular density (MVD) scoring involving CD34 antibody staining.

RESULTS

Fifty-nine patients were included in this study. The scores corresponding to the presence of short linear vessels, linear-curved vessels, branching linear vessels, and non- structured orange-colored areas were significantly higher in the MF patients than in the SPP patients (P < 0.05). The highest MVD (P = 0.01) scores were also higher in the MF patients than in the SPP patients.

CONCLUSIONS

The SPP and early-stage MF patients differed in their MVD scores, and the findings correlated with the dermatoscopy and lesional capillaroscopy findings. Differentiating features between SPP and MF were thus identified.

Histopathological Markers for Target Therapies in Primary Cutaneous Lymphomas

In recent years, targeted (biological) therapies have become available also for primary cutaneous T-cell lymphomas (PCTCLs) including anti-CD30 (brentuximab vedotin) in mycosis fungoides, primary cutaneous anaplastic large T-cell lymphoma, lymphomatoid papulosis; anti-CCR4 (mogamulizumab) in Sezary syndrome; anti-CD123 (tagraxofusp) in blastic plasmocytoid cell neoplasm. Moreover, anti-PD1 (nivolumab), anti-PDL1 (pembrolizumab, atezolizumab), anti-CD52 (alemtuzumab), anti-KIR3DL2-CD158k (lacutamab), and anti-CD70 (cusatuzumab) have been tested or are under investigations in phase II trials. The expression of these epitopes on neoplastic cells in skin biopsies or blood samples plays a central role in the management of PCTCL patients. This narrative review aims to provide readers with an update on the latest advances in the newest therapeutic options for PCTCLs.

CD30 expression in cutaneous B-cell lymphomas

INTRODUCTION

CD30 expression has been infrequently described in cutaneous B-cell lymphomas (CBCLs). We examined CD30 expression in reactive lymphoid hyperplasia (RLH) and CBCL and correlated expression with clinicopathologic features.

METHODS

CD30 was examined in 82 CBCL patients and 10 RLH patients that had been evaluated in our cutaneous lymphoma clinics. The CBCL patients included: primary cutaneous follicle center lymphoma (PCFCL), Grade 1/2 systemic/nodal follicular lymphoma (SFL); primary cutaneous marginal zone lymphoma/lymphoproliferative disorder (PCMZL/LPD); systemic marginal zone lymphoma (SMZL); primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT); and extracutaneous/systemic diffuse large B-cell lymphoma (eDLBCL). We scored CD30 expression for intensity and extent and related CD30 expression to age at first diagnosis, sex, site of biopsy, clinical appearance, extracutaneous involvement, multiple cutaneous lesions, B-symptoms, lymphadenopathy, positive positron emission tomography/computed tomography (PET/CT), elevated lactate dehydrogenase (LDH), and positive bone marrow biopsy.

RESULTS

CD30 expression was identified in 35% of CBCL, ranging from few, weak, scattered cells to strong and diffuse expression. It was most common in PCFCL and was not expressed in PCDLBCL-LT. Rare PCFCL expressed strong, diffuse CD30. Some cases of PCMZL/LPD, SMZL, FL, and RLH showed scattered, strongly positive cells. CD30 expression in CBCL was associated with favorable clinical features: younger age, negative PET/CT, and an LDH within normal limits.

CONCLUSIONS

CD30 may be expressed in CBCL, possibly causing diagnostic confusion. CD30 expression was most commonly identified in PCFCL and is associated with favorable clinical features. In cases with strong and diffuse expression, CD30 could be a therapeutic target.

Dermatophytosis Incognito Mimicking Cutaneous T-Cell Lymphoma

Dermatophytosis incognito can be missed in diagnosis, given its relatively low prevalence as compared with common cases of dermatophytosis and therefore, is likely under-reported. Cutaneous T-cell lymphoma (CTCL) is also a rare entity with variable clinical manifestations. While successful treatment of dermatophytosis is feasible withmultiple topical and systemic antifungal options, CTCL can present a therapeutic challenge associated with significant emotional distress for the patients. We present a case of tinea incognito initially treated for eczema, later considered biopsy-supported CTCL that was successfully treated with antifungal therapy.