Paediatric cutaneous lymphomas including rare subtypes: A 40-year experience at a tertiary referral centre

BACKGROUND

Primary cutaneous lymphomas are neoplasms of the immune system with a distinct tropism for the skin and an absence of extracutaneous manifestations at the time of diagnosis. Studies focusing on cutaneous lymphomas in children and adolescents remain scarce and often do not encompass the rare subtypes.

OBJECTIVES

To address this knowledge gap by describing the clinical, histological and molecular characteristics of a large group of paediatric patients affected by primary cutaneous lymphoma. We also provided the Paediatric Primary Cutaneous Lymphoma Atlas that illustrates the clinicopathological spectrum of observed presentations, in the hope of supporting other physicians in the diagnostic process.

METHODS

Retrospective chart review of paediatric patients diagnosed with primary cutaneous lymphomas between 1980 and 2022 at the Paediatric Dermatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan.

RESULTS

A total of 101 patients (58 males, 43 females) met the inclusion criteria. The most common subtypes were lymphomatoid papulosis (n = 48) and mycosis fungoides (n = 31). These were followed by primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders (n = 7), primary cutaneous anaplastic large-cell lymphomas (n = 5), primary cutaneous marginal zone B-cell lymphomas (n = 3), primary cutaneous follicle centre lymphomas (n = 2), subcutaneous panniculitis-like T-cell lymphomas (n = 2), primary cutaneous peripheral T-cell lymphoma not otherwise specified (n = 1), primary cutaneous precursor B-lymphoblastic lymphoma (n = 1) and Sézary syndrome (n = 1). Clinical follow-up data covering a median of 70.8 months (range 1-324) were available for 74 patients, of whom three died due to cutaneous lymphoma.

CONCLUSIONS

Our findings shed light on the peculiar aspects and long-term outcomes of paediatric cutaneous lymphomas, particularly emphasizing their distinctive features in comparison to their adult counterparts and exploring the less common subtypes. Further larger-scale studies are warranted to better characterize these entities and to achieve a more rapid and accurate diagnosis.

Uncommon neoplasms mistakenly diagnosed as hidradenitis suppurativa: Report of three consecutive cases

Hidradenitis suppurativa (HS) poses diagnostic challenges due to its clinical overlap with various skin conditions and neoplasms, potentially leading to misdiagnoses. The absence of a definitive diagnostic test and infrequent use of histopathology contribute to diagnostic complexities, exacerbated by the recent increased focus on HS. Three cases initially diagnosed and treated as HS underwent clinical work-up and skin biopsies to resolve diagnostic complexities. Initially labeled as HS, the cases revealed a breast carcinoma on axillary ectopic tissue, a cutaneous gamma-delta T-cell lymphoma, and an infiltrating squamous cell carcinoma. Delayed recognition led to misguided therapies and adverse outcomes. This report stresses the need to explore alternative diagnoses for chronic skin nodules with or without ulcerations on the flexures. Timely skin biopsies are crucial for accurate diagnoses. Ongoing clinician education is essential to avoid misdiagnosis in challenging cases, in which histopathology aids in reaching a correct diagnosis.

Primary cutaneous lymphoproliferations in the gray zone between marginal zone lymphoma and CD4+ small/medium T-cell lymphoproliferative disease

BACKGROUND

Primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disease (CD4+ TLPD) are two distinct entities with excellent prognosis; however, they show profound clinical and histopathological similarities, leading to differential diagnostic uncertainty.

AIMS

Our aim was to review and reanalyze cases of primary cutaneous lymphoproliferations diagnosed at Semmelweis University, featuring characteristics of PCMZL and CD4+ TLPD.

MATERIALS AND METHODS

Cutaneous lymphoma biopsy specimens between 2018 and 2022 were collected and re-evaluated. Medical history, clinical picture, imaging, and laboratory findings were collected. Immunohistochemical staining for CD20, CD3, BCL6, CD10, PD1, CD3, CD4, CD8, and PCR tests for IGH, IGK, TCRB, and TCRG were repeated in selected cases.

RESULTS

Among 55 cases diagnosed as PCMZL (16) or CD4+ TLPD (39), 3 patients had been diagnosed with both LPDs at different time points of their disease course. Four additional patients were identified with single lesions featuring overlapping histopathological characteristics of both LPDs and both monoclonal IGH and TCR rearrangements. All patients are currently in complete remission with local treatment.

CONCLUSION

We propose that besides the overlapping histopathological, molecular, and clinical features, the subsequent appearance of PCMZL and CD4+ TLPD in a short timeframe in the same patients may suggest a common pathogenic background.

Oncogenic alterations in KIR3DL1 in cutaneous acral CD8+ lymphoproliferative disorder

BACKGROUND

Primary cutaneous acral CD8+ T-cell lymphoproliferative disorder (TLPD) is a rare and indolent lymphoma entity. Although TLPD was first identified many years ago, the molecular pathogenesis is still not fully understood.

OBJECTIVES

In order to better understand the molecular pathogenesis of cutaneous acral CD8+ TLPD and to identify further discriminatory markers to differentiate this lymphoma subtype from other CD8+ cutaneous lymphomas, we analysed five cases of cutaneous acral CD8+ TLPD for putative molecular alterations.

METHODS

Somatic alterations were assessed using whole-exome and targeted sequencing of paraffin-embedded tissue. Results were evaluated using immunohistochemical staining of respective relevant proteins. CD8+ cutaneous T-cell lymphomas (n = 12) served as control for KIR3DL1 staining.

RESULTS

Copy number variation analysis revealed a homozygous deletion of the KIR3DL1 gene in two of the analysed cases. This resulted in loss of KIR3DL1 protein expression, which was observed in all cases of cutaneous acral CD8+ TLPD. In contrast, KIR3DL1 expression was more variable in other CD8+ cutaneous T-cell lymphomas with 50% of analysed cases (n = 12) found to be positive. In addition, one further case of acral CD8+ TLPD harboured a loss-of-function mutation in the PIK3R1 gene, presumably activating the phosphoinositide 3-kinase-AKT pathway.

CONCLUSIONS

Alterations of the KIR3DL1 gene may be of pathogenetic relevance for acral CD8+ TLPD. Loss of KIR3DL1 protein expression may support the diagnosis of this indolent lymphoma entity; however, this is not a subtype-specific discriminative feature.

Cutaneous T-cell Lymphoma

Cutaneous T-cell lymphoma is a group of non-Hodgkin T-cell lymphomas that develop in and affect the skin but can potentially spread to other organs. There are many subtypes, the most common of which are mycosis fungoides, Sezary syndrome, lymphomatoid papulosis, and primary cutaneous anaplastic large cell lymphoma. Cutaneous lymphoma is a common cause of recalcitrant chronic skin rash and notoriously mimics other dermatologic and hematologic conditions, often resulting in diagnostic delays of months to years. This review provides an introduction to cutaneous T-cell lymphoma, with a primary focus on the clinical presentation, diagnosis, immunopathogenesis, and management of the condition.

Assessing T-cell receptor clonality by next-generation sequencing in atypical cutaneous lymphoid infiltrates and cutaneous T-cell lymphoma: A scoping review

The diagnosis of cutaneous T-cell lymphoma (CTCL) remains challenging. Demonstration of a clonal T-cell population using T-cell receptor (TCR) gene rearrangement studies by next-generation sequencing (NGS) has been explored in several studies. This review summarizes the current literature on NGS-based sequencing methods for the assessment of TCR clonality in the evaluation of atypical cutaneous lymphoid infiltrates and CTCL on behalf of the American Society of Dermatopathology Appropriate Use Criteria Committee (lymphoproliferative subgroup). PubMed was searched for relevant articles, including CTCL and NGS, for clonality from 1967 to 2022. Thirteen studies were included in the analysis. The skin was the most commonly assayed compartment with TCR NGS. Sensitivity for TCR NGS in the skin ranged between 69% and 100%, compared to 44%-72% for polymerase chain reaction (PCR)-capillary electrophoresis. Specificity for TCR NGS in the skin ranged from 86% to 100%, compared to 77%-88% for PCR capillary electrophoresis. TCR NGS was also reported to have potential prognostic value in CTCL and can also be used to detect relapse and/or minimal residual disease after treatment.

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.

Navigating Diagnostic and Therapeutic Challenges in Primary Cutaneous Gamma/Delta T-Cell Lymphoma: A Case Study of Fatal Outcomes Within Two Months

ABSTRACT

Primary cutaneous gamma/delta T-cell lymphoma (PCGD-TCL) is a rare yet highly aggressive subtype of primary cutaneous lymphoma. Characterized by its challenging diagnosis and poor prognosis, PCGD-TCL presents unique clinical and histopathological features that distinguish it from other primary cutaneous lymphoma subtypes. Here, we report the case of a 75-year-old man who initially presented with multiple erythematous indurated plaques over his back and bilateral lower extremities. The initial biopsy suggested primary cutaneous T-cell lymphoma (PCTCL) with a CD30-negative phenotype. However, within a 2-month interval, the disease progressed rapidly, manifesting as extensive skin involvement across the chest and upper extremities. A repeat skin biopsy was performed, revealing dermal atypical lymphocytes without epidermotropism. Immunohistochemical analysis demonstrated positivity for CD3, CD5, and CD4, as well as T-cell receptor delta (TCR delta) expression, along with the loss of CD8 and CD30 expression. These findings were consistent with a diagnosis of PCGD-TCL. Despite therapeutic interventions, including systemic treatments, the patient's condition deteriorated rapidly, ultimately leading to his demise within a month of receiving the PCGD-TCL diagnosis. This case highlights the diagnostic complexities associated with PCGD-TCL, emphasizing the importance of careful histopathological examination and immunophenotypic characterization. Given its aggressive nature and propensity for rapid dissemination, early recognition of PCGD-TCL is paramount for initiating appropriate therapeutic interventions. However, effective treatment options for PCGD-TCL remain limited, and the disease typically carries an unfavorable prognosis. Further research is needed to elucidate the underlying molecular mechanisms driving the pathogenesis of PCGD-TCL, to identify novel therapeutic targets, and to improve patient outcomes. In addition, increased awareness among clinicians and pathologists regarding the clinical presentation and diagnostic criteria of PCGD-TCL is crucial for facilitating timely diagnosis and management of this challenging malignancy.

Primary cutaneous, epidermotropic mycosis fungoides-like presentation: critical appraisal and description of two novel cases, broadening the spectrum of ALK+ T-cell lymphoma

Leading from a two-case series, including two patients receiving a diagnosis of epidermotropic T-cell lymphoma, featuring a mycosis fungoides (MF)-like clinical pattern and ALK expression and molecular alteration, we performed a critical appraisal of ALK+ primary cutaneous T-cell lymphomas (pcTCL). Considering our patients and the literature, 32 cases were retrieved, 7 of which featured an MF-like clinical picture over a 4-to-20-year period. MF-like cases show distinctive histology, comprising a predominantly epidermotropic infiltration of small-to-large, atypical-to-pleomorphic, with few anaplastic cells, negligible-to-intense CD30-expression, and a CD4+/cytotoxic granule+ phenotype. These features should prompt a search for ALK expression captured by the ALK D5F3 clone. Bona fide ALK+ pcTCL is very rare, and existent data suggest the presence of a broader pattern of disease, including instances mimicking MF and/or primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma. The major challenges in dealing with this subset include prodromal phases, misinterpreted as inflammatory dermatosis or parapsoriasis/early phase MF both clinically and histologically, while recognition of its ALK-driven biology is hampered both by the unusual clinic-pathologic pattern of the disease, which stands apart from the classical (i.e., nodal) picture of ALK+ anaplastic large cell lymphoma and by the low sensitivity of ALK1 clone. Data on its optimal management are far from being conclusive: An MF-like approach is currently chosen, but depending on CD30 and, most notably, ALK expression, a targeted therapy could be envisaged in advanced stages, as clinical response to ALK inhibition was documented in one patient.

Updated cutaneous T-cell lymphoma TNMB staging criteria fail to identify patients with Sézary syndrome with low blood burden

Comparison of the 2007 EORTC/ISCL and the 2022 EORTC/ISCL/USCLC blood staging guidelines for cutaneous T-cell lymphoma at a single institution reveals the newer guidelines fail to detect a subset of patients with Sézary syndrome with low blood burden.

Classifications of cutaneous lymphomas and lymphoproliferative disorders: An update from the EORTC cutaneous lymphoma histopathology group

The classification of primary cutaneous lymphomas and lymphoproliferative disorders (LPD) is continuously evolving by integrating novel clinical, pathological and molecular data. Recently two new classifications for haematological malignancies including entities of cutaneous lymphomas were proposed: the 5th edition of the WHO classification of haematolymphoid tumours and the International Consensus Classification (ICC) of mature lymphoid neoplasms. This article provides an overview of the changes introduced in these two classifications compared to the previous WHO classification. The main changes shared by both classifications include the downgrading of CD8+ acral T-cell lymphoma to CD8+ acral T-cell LPD, and the recognition of entities that were previously categorized as provisional and have now been designated as definite types including primary cutaneous small or medium CD4+ T-cell LPD, primary cutaneous gamma/delta T-cell lymphoma, primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, Epstein-Barr virus-positive mucocutaneous ulcer. Both classifications consider primary cutaneous marginal zone B-cell clonal neoplasm as an indolent disease but use a different terminology: primary cutaneous marginal zone lymphoma (WHO) and primary cutaneous marginal zone LPD (ICC). The 5th WHO classification further introduces and provides essential and desirable diagnostic criteria for each disease type and includes chapters on reactive B- or T-cell rich lymphoid proliferations formerly referred as cutaneous pseudolymphomas, as well as histiocyte and CD8 T-cell rich LPD in patients with inborn error of immunity. As already emphasized in previous lymphoma classifications, the importance of integrating clinical, histological, phenotypic and molecular features remains the crucial conceptual base for defining cutaneous (and extracutaneous) lymphomas.

Pathophysiology of cutaneous T-cell lymphomas: Perspective from a French referral centre

Cutaneous T-cell lymphomas (CTCL) are a diverse group of malignant blood disorders characterized by initial skin infiltration, and sometimes, tumor spreading to lymph nodes, blood, and viscera. Mycosis fungoides is the most common form. Sézary syndrome is a distinctive form of CTCL marked by a significant presence of circulating tumor cells in peripheral blood. These diseases are characterized by the plasticity and heterogeneity of the tumor cells in the different tissue compartments, and a difficulty in identifying these tumor cells for diagnostic purposes and therapeutic monitoring. Progress has been made in the understanding of the pathophysiology of these diseases in recent years, and we provide here a review of these advancements.

Cutaneous T-cell Lymphoma Diagnostic and Therapeutic Trends amidst the COVID-19 Pandemic

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Cutaneous lymphoproliferative disorders: Back to the future

In the 1980s, immunohistochemistry and clonality analyses became instrumental in the recognition and definition of new types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL) and the development of new classifications. By accepting loss of pan-T-cell antigens and clonal T-cell receptor gene rearrangements as important criteria to differentiate between benign and malignant T-cell proliferations, and monotypic immunoglobulin light-chain expression and clonal immunoglobulin gene rearrangements as crucial criteria to distinguish between benign and malignant B-cell proliferations, many cases, until then diagnosed as cutaneous lymphoid hyperplasia or pseudolymphoma, were reclassified as primary cutaneous CD4+ small/medium T-cell lymphoma (PCSM-TCL) or primary cutaneous marginal zone lymphoma (PCMZL), respectively. However, in recent years there is growing awareness that neither these immunohistochemical criteria nor demonstration of T-cell or B-cell clonality is specific for malignant lymphomas. In addition, many studies have reported that these low-grade malignant CTCL and CBCL have an indolent clinical behavior and an excellent prognosis with disease-specific survival rates of or close to 100%. As a result, recent classifications have downgraded several low-grade malignant cutaneous lymphomas to lymphoproliferative disorder (LPD). Both the 5th edition of the WHO classification (2022) and the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms reclassified PCSM-TCL as primary cutaneous CD4+ small/medium T-cell LPD and primary cutaneous acral CD8+ T-cell lymphoma as primary cutaneous acral CD8+ T cell LPD. While the 2022 ICC introduced the term "primary cutaneous marginal zone LPD," in the 5th edition of the WHO classification PCMZL is maintained. In this review we describe the background and rationale of the continually changing terminology of these conditions and discuss the clinical consequences of downgrading malignant lymphomas to LPDs.

Adrenal Insufficiency after Long-term use of Topical Glucocorticoids in Patients with Advanced Cutaneous T-cell Lymphomas: A Case Series

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Application of Blood Lymphocyte Immunophenotype and TCR Gene Rearrangement in the Diagnosis of CTCL

BACKGROUND

The immunophenotype of peripheral blood lymphocytes and T-cell receptor (TCR) gene rearrangement of cutaneous T cell lymphoma (CTCL) patients were retrospectively analyzed to explore their value in the diagnosis of CTCL.

METHODS

A total of fifty patients' results were enrolled from 2013 to 2021, including 29 malignant skin disorders and 21 benign skin disorders. The immunophenotype of peripheral blood lymphocytes were analyzed by flow cytometry and TCR gene rearrangement was detected by capillary electrophoresis. Lymphocyte subsets, CD4/CD8 ratio, the percentage of CD3+CD4+CD7- cells and CD45RA/CD45RO ratio was calculated between malignant and benign skin disorders. Peripheral blood lymphocyte immunophenotype and TCR gene rearrangement was compared with skin biopsy to evaluate their sensitivity and specificity.

RESULTS

Lymphocyte subsets between malignant and benign groups have no significant difference in percentage of T cell (p > 0.05). The CD4/CD8 ratio is higher in patients with malignant lymphoma than the healthy range. The percentage of CD3+CD4+CD7- cells in malignant groups is higher than that in benign groups and CD45RA/ CD45RO ratio has significant difference between malignant and benign groups (p < 0.05). The sensitivity and specificity of TCR rearrangement for CTCL were 51.7% and 42.9%. The sensitivity and specificity of peripheral blood lymphocyte immunophenotype for CTCL were 44.8% and 33.3%. Combining the two methods, the sensitivity and specificity reached 69.0% and 38.1%, respectively.

CONCLUSIONS

CD4/CD8 ratio of lymphocyte subsets, the proportion of CD4+CD7-T cells and CD45RA/CD45RO ratio can effectively distinguish benign and malignant dermatosis. TCR rearrangement method combined with lymphocyte immunophenotype can improve the sensitivity and specificity of CTCL diagnosis.

Subcutaneous Panniculitis-Like T-Cell Lymphoma With Hemophagocytic Lymphohistiocytosis

Subcutaneous panniculitis-like T-cell lymphoma (SPTLP), a unique variant of primary cutaneous T-cell lymphomas, clinically mimics subcutaneous panniculitis. It is typified by the development of multiple plaques or subcutaneous erythematous nodules, predominantly on the extremities and trunk. Epidemiological findings reveal a greater incidence in females than males, affecting a wide demographic, including pediatric and adult cohorts, with a median onset age of around 30 years. Diagnosis of SPTLP is complex, hinging on skin biopsy analyses and the identification of T-cell lineage-specific immunohistochemical markers. Treatment modalities for SPTLP are varied; while corticosteroids may be beneficial initially for many patients, a substantial number require chemotherapy, especially in cases of poor response or relapse. Generally, SPTLP progresses slowly, yet approximately 20% of cases advance to hemophagocytic lymphohistiocytosis (HLH), often correlating with a negative prognosis. We report a case of a young male patient presenting with prolonged fever, multiple skin lesions accompanied by HLH, a poor clinical course, and eventual death, diagnosed postmortem with SPTLP. In addition, we also present a literature review of the current evidence of some updates related to SPTLP.