Cutaneous CD8+ Cytotoxic T-Cell Lymphoma Infiltrates: Clinicopathological Correlation and Outcome of 35 Cases

Comment on 'Oncogenic alterations in KIR3DL1 in cutaneous acral CD8+ lymphoproliferative disorder' by Wobser et al

Identifying pathognomonic features that differentiate primary cutaneous acral CD8+ T-cell lymphoproliferative disorder (TLPD) from other CD8+ aggressive lymphomas is a major concern. Doing so can facilitate diagnosis and allow clinicians to optimize clinical management. In this context, we read with great interest the article from Wobser et al., which proposed a molecular characterization of five cutaneous acral CD8+ TLPDs and identified KIR3DL1 alterations in addition to PIK3R1 alterations. To broaden this spectrum, we propose genomic profiling of six cutaneous acral CD8+ TLPDs from our database and identify alterations related to oncogenic pathways such as the AKT pathway and the Janus kinase–signal transducer and activator of transcription protein pathway. We also confirm the decreased mRNA expression of KIR3DL1 in this setting.

Primary Cutaneous Acral CD8-Positive Lymphoproliferative Disorder: A Case Report With Nonacral Presentation

In this study, we describe a patient of primary cutaneous acral CD8-positive lymphoproliferative disorder located in a nonacral region. A 65-year-old male presented with an ill-defined lesion of rubbery consistency and a maximum diameter of 2.5 cm localized in the right thigh. Histologically, it was composed of a diffuse dermal infiltration of medium-sized atypical lymphocytes that expressed CD3, CD8, and TIA-1. In addition, a characteristic paranuclear positivity with CD68 was observed. During the follow-up, the patient had a recurrence of the disease in the abdomen with a lesion showing similar morphology and phenotype. To our knowledge, < 20 patients of primary cutaneous acral CD8-positive lymphoproliferative disorder with a nonacral presentation have been described in English literature. Although rare, its identification is essential to differentiate it from other T-cell lymphoma that express CD8 and cytotoxic markers, and whose clinical courses are very aggressive.

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.

Primary Cutaneous Peripheral T-Cell Lymphoma NOS: Diagnostic Criteria and Challenges

ABSTRACT

Primary cutaneous peripheral T-cell lymphoma not otherwise specified (PTCL NOS) denotes lymphomas that do not conform to a recognized entity. Within this category, 3 specific lymphoproliferative diseases had been granted provisional status pending further confirmation of their validity as distinct entities; acral CD8+ lymphoma-recently accepted as acral CD8+ lymphoproliferative disorder-aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma, and CD4+ small-medium T-cell lymphoproliferative disorder. The adoption of stringent diagnostic criteria, which include clinical, morphological, and immunohistochemical data, and some inherent variations of these within individual cases, raises problems as to the boundaries between these tumors and a diagnosis of PTCL NOS. This review discusses the evolution of our knowledge of these tumors and their diagnostic criteria with respect to the wider PTCL NOS category.

Interface change in early mycosis fungoides: A potential mimicker of benign dermatoses

BACKGROUND

Histopathologic features of interface dermatitis can occasionally be seen in mycosis fungoides (MF), particularly in early patch-stage disease.

MATERIALS AND METHODS

We identified six patients with MF whose early biopsy specimens showed such prominent interface dermatitis that a benign diagnosis was favored. All subsequent specimens were reviewed for these patients, and the histopathologic evolution of disease was documented. Immunohistochemistry (IHC) for CD2, CD3, CD4, CD5, CD7, CD8, CD30, and CD123 was performed retrospectively. Educational archives were reviewed to assess the incidence of interface dermatitis in biopsies otherwise diagnostic of MF.

RESULTS

A spectrum of vacuolar and lichenoid patterns of interface change was observed in this series of six patients eventually diagnosed as having MF, and was seen as a recurring pattern in multiple specimens over time. In retrospect, findings described in early MF such as lining up of lymphocytes along the dermal-epidermal junction within the basal layer, papillary dermal fibrosis, and intraepidermal lymphocyte atypia could be appreciated to varying degrees in the confounding specimens. CD123 was negative in all cases, putatively excluding a connective tissue disease (CTD). None of the early biopsies showed loss of pan-T antigens CD2, CD5, and CD7. Forty-six of 164 cases (28%) of MF in an archival study set showed varying degrees of interface dermatitis in the setting of otherwise diagnostic changes of MF.

CONCLUSIONS

Early MF can show prominent interface change and mimic inflammatory dermatoses. Histopathologic clues suggestive of MF should be carefully assessed, and IHC for CD123 may be helpful in distinguishing MF from CTD. Repeat biopsies over time may be necessary to arrive at a definitive diagnosis, in conjunction with ancillary studies and strong clinicopathologic correlation.

An accurate diagnosis of dermal CD8+ lymphoproliferative disorders requires clinicopathological and immunophenotypic correlation

Linked Article: Kempf et al. Br J Dermatol 2022; 186:887–897.

Tumor Immune Microenvironment in Lymphoma: Focus on Epigenetics

Lymphoma is a neoplasm arising from B or T lymphocytes or natural killer cells characterized by clonal lymphoproliferation. This tumor comprises a diverse and heterogeneous group of malignancies with distinct clinical, histopathological, and molecular characteristics. Despite advances in lymphoma treatment, clinical outcomes of patients with relapsed or refractory disease remain poor. Thus, a deeper understanding of molecular pathogenesis and tumor progression of lymphoma is required. Epigenetic alterations contribute to cancer initiation, progression, and drug resistance. In fact, over the past decade, dysregulation of epigenetic mechanisms has been identified in lymphomas, and the knowledge of the epigenetic aberrations has led to the emergence of the promising epigenetic therapy field in lymphoma tumors. However, epigenetic aberrations in lymphoma not only have been found in tumor cells, but also in cells from the tumor microenvironment, such as immune cells. Whereas the epigenetic dysregulation in lymphoma cells is being intensively investigated, there are limited studies regarding the epigenetic mechanisms that affect the functions of immune cells from the tumor microenvironment in lymphoma. Therefore, this review tries to provide a general overview of epigenetic alterations that affect both lymphoma cells and infiltrating immune cells within the tumor, as well as the epigenetic cross-talk between them.

Primary cutaneous CD8+ cytotoxic T-cell lymphoma of the face with intraoral involvement, presenting facial nerve palsy after chemotherapy

The primary cutaneous (PC) CD8+ T-cell lymphoproliferative disorders (LPDs) comprise clinically and histologically heterogeneous entities including mycosis fungoides, lymphomatoid papulosis, hydroa-vacciniforme-like LPD, subcutaneous panniculitis-like T-cell lymphoma (TCL), PC acral CD8+ TCL, PC CD8+ aggressive epidermotropic cytotoxic TCL, and PC peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). We describe a 33-year-old man who presented progressive facial swelling and lower lip involvement one year ago. Microscopy revealed an atypical small to medium-sized lymphoid proliferation exhibiting perivascular accentuation, adnexotropism and apoptotic cell debris, without surface epithelium involvement. The tumor cells were positive for CD3, CD8, granzyme B, perforin, MUM1/IRF4, and TCR-BF1. The Ki-67 labeling index was 48%. EBER1/2 was negative. Additional studies confirmed localized disease. The diagnosis favored PC-PTCL-NOS. Two months after completing chemotherapy, right-sided facial nerve palsy was diagnosed. CD8+ T-cell LPDs should be considered in the differential diagnosis when assessing facial swelling with intraoral involvement. This article is protected by copyright. All rights reserved.

Solitary CD8-Positive Primary Cutaneous Peripheral T-Cell Lymphoma: A Question of Classification

ABSTRACT

Acral CD8(+) lymphoma is a provisional entity in the latest edition of the WHO Lymphoma Classification and is associated with a highly specific dot-like pattern of immunohistochemical expression of CD68. We report a case of an ulcerated solitary cutaneous lesion arising on the forehead of an adult man, which had a CD8(+) cytotoxic phenotype and areas of dot-like CD68 positivity, but with a number of features that significantly detracted from the classically described acral CD8(+) lymphoma. The nosological status of the lesion is discussed with respect to a preferred diagnosis of peripheral T-cell lymphoma, not otherwise specified.

Indolent CD8+ primary cutaneous T-cell lymphoma involving the eyelid of an adolescent

Primary cutaneous acral CD8+ T-cell lymphoma (PCACTL) is currently a provisional entity defined as a rare cutaneous proliferation of atypical CD8+ lymphocytes that preferentially involves acral sites and has a good prognosis. We present a case of primary cutaneous CD8+ T-cell lymphoma involving the eyelid of an adolescent male. The case shares features with PCACTL, including indolent clinical behavior and expression of CD68 in a Golgi-associated dot-like pattern; however, other features differ significantly from PCACTL as currently defined by the World Health Organization (WHO). These features include ulceration, expression of CD56, granzyme B, and perforin, and a high proliferative index. Given these discrepancies, our case is currently best classified as a CD8+ primary cutaneous peripheral T-cell lymphoma, not otherwise specified. We review the differential diagnosis for this case and suggest expanding the definition of PCACTL.

Article Topic/Title: Primary cutaneous T-cell lymphomas other than Mycosis Fungoides and Sezary Syndrome. Part II: Prognosis and Management

Primary cutaneous T-cell lymphomas (CTCLs) other than Mycosis Fungoides (MF) and Sézary syndrome (SS) encompass a heterogenous group of non-Hodgkin lymphomas with variable clinical course, prognoses, and management. With morphologic and histologic overlap among the CTCL subtypes and other T-cell lymphomas with cutaneous manifestations, thorough evaluation with clinicopathologic correlation and exclusion of systemic involvement are essential prior to initiating therapy. Staging and treatment recommendations vary depending on the subtype, clinical behavior, and treatment response. Generally, for subtypes where staging is recommended, Ann Arbor or TNM staging specific to CTCL other than MF or SS are used. For many subtypes, there is no standard treatment to date. Available recommended treatments range widely from no active or minimal intervention with skin-directed therapy to aggressive systemic therapies including multiagent chemotherapy with consideration for hematopoietic stem cell transplant. Emerging targeted therapies, such as brentuximab, a chimeric antibody targeting CD30, show promise in altering the disease course of non-MF/SS CTCLs.

Lost in the Clinics and Found in the Morgue: A Case of Peripheral T-cell Lymphoma Masquerading as Pneumonia

In modern medicine, there is an increasing dependence on noninvasive imaging modalities, for diagnosis and management of diseases. Though there are definite advantages to this, they are at times offset by diagnostic pitfalls especially in entities with elusive clinical presentation.Peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) is an aggressive subtype of T-cell lymphomas that does not meet criteria for a specific subtype. Peripheral T-cell lymphoma usually has varied clinical presentations depending on the site of involvement. Vast majority of PTCL patients present with systemic disease, generalized lymphadenopathy and constitutional symptoms. Pulmonary involvement is relatively rare and is seen in approximately 10% of patients.Here in we highlight a rare case of PTCL, masquerading as pneumonia due to extensive pulmonary involvement that went undiagnosed and was discovered at autopsy. This case of malignant lymphoma of T-cell origin involving the lung, which is very rare, highlights the continued importance of medical autopsies not only as a teaching tool but also as an important adjunct to investigative medicine in uncovering lapses that can subsequently be avoided to improve patient care and decrease mortality.

Primary cutaneous peripheral T-cell lymphoma, not otherwise specified: results of a multicentre European Organization for Research and Treatment of Cancer (EORTC) cutaneous lymphoma taskforce study on the clinico-pathological and prognostic features

BACKGROUND

Cutaneous peripheral T-cell lymphoma, not otherwise specified (PTL NOS) is an aggressive, but poorly characterized neoplasm.

OBJECTIVES

The European Organization for Research and Treatment of Cancer cutaneous lymphoma taskforce (EORTC CLTF) investigated 33 biopsies of 30 patients with primary cutaneous PTL NOS to analyse their clinical, histological, immunophenotypic features and outcome.

METHODS

Retrospective analysis of clinical data and histopathological features by an expert panel.

RESULTS

Cutaneous PTL NOS manifested clinically either with solitary or disseminated rapidly grown ulcerated tumours or disseminated papulo-nodular lesions. Histologically, a mostly diffuse or nodular infiltrate in the dermis and often extending into the subcutis was found. Epidermotropism was rarely present and only mild and focal. Unusual phenotypes were frequent, e.g. CD3⁺ /CD4^- /CD8^- and CD3⁺ /CD4⁺ /CD8⁺ . Moreover, 18% of the cases exhibited an aberrant expression of the B-cell marker CD20 by the tumour cells. All solitary tumours were located on the limbs and presented a high expression of GATA-3 but this did not correlate with outcome and therefore could not serve as a prognostic factor. The prognosis was shown to be generally poor with 10 of 30 patients (33%) dying of lymphoma within the follow-up of 36 months (mean value; range 3-144). The survival rates were 61% after 3 years (CI, 43-85%) and 54% after 5 years (CI, 36-81%). Small to medium-sized morphology of tumour cells was associated with a better outcome than medium to large or large tumour cells. Age, gender, clinical stage, CD4/CD8 phenotype and GATA-3 expression were not associated with prognosis. Chemotherapy was the most common treatment modality, but surgical excision and/or radiotherapy may represent an appropriate first-line treatment for solitary lesions.

CONCLUSIONS

Cutaneous PTL NOS shows an aggressive course in most patients independent of initial presentation, age and phenotype. Cytomorphology was identified as a prognostic factor. The data indicate a need for more effective treatment modalities in PTL NOS.

B Cells versus T Cells in the Tumor Microenvironment of Malignant Lymphomas. Are the Lymphocytes Playing the Roles of Muhammad Ali versus George Foreman in Zaire 1974?

Malignant lymphomas are a heterogeneous group of malignancies that develop both in nodal and extranodal sites. The different tissues involved and the highly variable clinicopathological characteristics are linked to the association between the lymphoid neoplastic cells and the tissues they infiltrate. The immune system has developed mechanisms to protect the normal tissue from malignant growth. In this review, we aim to explain how T lymphocyte-driven control is linked to tumor development and describe the tumor-suppressive components of the resistant framework. This manuscript brings forward a new insight with regard to intercellular and intracellular signaling, the immune microenvironment, the impact of therapy, and its predictive implications. A better understanding of the key components of the lymphoma environment is important to properly assess the role of both B and T lymphocytes, as well as their interplay, just as two legendary boxers face each other in a heavyweight title final, as was the case of Ali versus Foreman.

C-C chemokine receptor 4 expression in CD8+ cutaneous T-cell lymphomas and lymphoproliferative disorders, and its implications for diagnosis and treatment

AIMS

Patients with aggressive CD8+ cutaneous T-cell lymphomas (CTCLs) progress rapidly and respond poorly to therapy. Confounding treatment planning, there is clinicopathological overlap between aggressive CD8+ CTCLs and other lymphoproliferative disorders (LPDs). Hence, improved diagnostic methods and therapeutic options are needed. The aim of this study was to examine C-C chemokine receptor 4 (CCR4) expression as a diagnostic and therapeutic biomarker in CD8+ CTCLs/LPDs.

METHODS AND RESULTS

Forty-nine cases (41 patients) with CD8+ CTCLs/LPDs were examined, including CD8+ mycosis fungoides (MF) (n = 14), aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma (AETCL) (n = 8), subcutaneous panniculitis-like T-cell lymphoma (SPTCL) (n = 7), CD30+ LPDs (n = 6), primary cutaneous γδ T-cell lymphoma (GDTCL) (n = 6), and others (n = 8). Immunohistochemical tissue staining was performed with a CCR4 monoclonal antibody on formalin-fixed paraffin-embedded tissue sections. CCR4 immunostaining was graded as percentage infiltrate, i.e. high (>25%) and low (≤25%), and the results were correlated with clinicopathological diagnoses. CCR4 expression was seen in 69% of the studied cases. Any CCR4 positivity was seen in all CD8+ MF cases, in 83% of CD30+ LPD cases, in 75% of AETCL cases, in 33% of GDTCL cases, and in none of the SPTCL cases. High CCR4 expression was seen in 79% of CD8+ MF cases versus 33% of CD30+ LPD cases, in 17% of GDTCL cases, and in 12.5% of AETCL cases. Patients with more advanced MF stage had higher CCR4 expression.

CONCLUSIONS

CCR4 immunohistochemistry may be an adjunct in distinguishing advanced CD8+ MF from other CD8+ CTCLs/LPDs. Although CCR4 expression may justify therapeutic targeting of this receptor in CD8+ MF, the role of such therapies in other CD8+ CTCLs/LPDs is not yet clear.

Rare T-Cell Subtypes

There are a number of rare T-cell lymphoma subtypes that may be encountered in clinical practice. In recent years, improved immunohistochemical techniques and molecular tumor profiling have permitted refinement of some of the diagnostic categories in this group, as well as the recognition of distinct conditions not previously well elucidated. In this chapter, we cover the diagnostic and clinical features of some of the more common of these conditions, including subcutaneous panniculitis-like T-cell lymphoma, cutaneous gamma-delta T-cell lymphoma, enteropathy-associated T-cell lymphoma, monomorphic epitheliotropic intestinal T-cell lymphoma, primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma, CD4-positive small/medium T-cell lymphoproliferative disorder, and acral CD8-positive T-cell lymphoma. Given the rarity of these conditions, optimal treatments approaches are not always well established, not least as data from large-scale clinical trials are lacking. In this chapter, we aim to provide a summation of current thinking around best treatment, as well as highlighting some controversies in the management of these diagnoses.

Cutaneous Lymphomas with Cytotoxic Phenotype

Primary cutaneous cytotoxic lymphomas are T-cell or natural killer-cell lymphomas that express 1 or more cytotoxic markers. These neoplasms constitute a spectrum of diseases. In this review, an overview of clinical, morphologic, and phenotypical features of each subtype is provided. Differential diagnosis is discussed with attention to scenarios in which diagnostic difficulties are most frequently encountered.