Subcutaneous, Blastic Natural Killer (NK), NK/T-cell, and Other Cytotoxic Lymphomas of the Skin: A Morphologic, Immunophenotypic, and Molecular Study of 50 Patients

Subcutaneous panniculitis-like T-cell lymphoma and lupus erythematosus profundus: a diagnostic dilemma

A white Caucasian woman in her 30s presented with an indurated lesion on her right upper arm. Panniculitis was clinically suspected. Antinuclear antibody testing was positive but incisional biopsy showed subcutaneous panniculitis-like T-cell lymphoma (SPTCL), although with some unusual features more in keeping with lupus. Initial treatment was with oral prednisolone and radiotherapy but with only partial response. A second biopsy was taken from an area of presumed residual disease. This displayed histological features that were much more typical of lupus erythematosus profundus (LEP) but with tiny foci suggesting concomitant microscopic areas of SPTCL. Immunofluorescence for IgM was positive. This case highlights the rare occurrence of a patient with overlapping clinical and pathological features of SCPTL and LEP. It emphasises the need for close clinicopathological correlation in the workup of patients with suspected panniculitis and the importance of careful pathological examination for features of both diseases.

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.

Primary Cutaneous Multifocal Indolent CD8+ T-Cell Lymphoma: A Novel Primary Cutaneous CD8+ T-Cell Lymphoma

We report the case of a patient who was referred to our institution with a diagnosis of CD4+ small/medium-sized pleomorphic lymphoma. At the time, the patient showed a plethora of lesions mainly localizing to the legs; thus, we undertook studies to investigate the lineage and immunophenotype of the neoplastic clone. Immunohistochemistry (IHC) showed marked CD4 and CD8 positivity. Flow cytometry (FCM) showed two distinct T-cell populations, CD4+ and CD8+ (+/- PD1), with no CD4/CD8 co-expression and no loss of panT-cell markers in either T-cell subset. FCM, accompanied by cell-sorting (CS), permitted the physical separation of four populations, as follows: CD4+/PD1-, CD4+/PD1+, CD8+/PD1- and CD8+/PD1+. TCR gene rearrangement studies on each of the four populations (by next generation sequencing, NGS) showed that the neoplastic population was of T-cytotoxic cell lineage. IHC showed the CD8+ population to be TIA-1+, but perforin- and granzyme-negative. Moreover, histiocytic markers did not render the peculiar staining pattern, which is characteristic of acral CD8+ T-cell lymphoma (PCACD8). Compared to the entities described in the 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas, we found that the indolent lymphoma described herein differed from all of them. We submit that this case represents a hitherto-undescribed type of CTCL.

Etiopathogenesis, Diagnosis, and Treatment Strategies for Lymphomatoid Papulosis with Particular Emphasis on the Role of the Immune System

Lymphomatoid papulosis (LyP) is a very rare disease that belongs to the group of CD30+ lymphoproliferative skin diseases. LyP is localized or generalized and usually presents as isolated or clustered red/brown-red lesions in the form of nodules and/or papules. The course of the disease is in most cases mild; however, depending on concomitant risk factors and history, it may progress to lymphoma, significantly reducing the survival rate and prognosis. Importantly, the clinical picture of the disease remains somewhat ambiguous, leading to a large number of misdiagnoses that result in inappropriate treatment, which is usually insufficient to alleviate symptoms. In addition to clinical manifestations, the histological characteristics vary widely and usually overlap with other conditions, especially those belonging to the group of lymphoproliferative disorders. Although diagnosis remains a challenge, several recommendations and guidelines have been introduced to standardize and facilitate the diagnostic process. This article reviews the available literature on the most important aspects of etiopathogenesis, clinical and histopathological features, diagnostic criteria, and possible treatment strategies for LyP, with particular emphasis on the role of the immune system.

Cutaneous Involvement of Extranodal NK/T Cell Lymphoma, Nasal Type, a Clinical and Histopathological Mimicker of Various Skin Diseases

Background: Extranodal NK/T cell lymphoma, nasal type (ENK/T) with cutaneous involvement has various histopathological findings and diverse clinical manifestations. Methods: A retrospective study of cutaneous involvement of ENK/T lymphoma between 2006 and 2018 was conducted. Results: Twenty-two cases were eligible for this study. Twelve cases could be proven as secondary cutaneous involvement by ENK/T lymphoma, while the remaining could not be confirmed as primary cutaneous ENK/T lymphoma. The histopathological patterns included dermal and subcutaneous nodular infiltration pattern in 11/22 cases (50%), lobular panniculitis pattern in 6/22 cases (27.3%), interface dermatitis pattern in 4/22 cases (18.2%), and granulomatous dermatitis pattern in 1/22 case (4.5%). The median follow-up was 18.3 months. Overall, the one-year and five-year survival rates were 31.3% and 13.3%, respectively. Conclusions: A variety of histopathological patterns of cutaneous involvement by ENK/T lymphoma should be differentiated from other cutaneous lymphomas, dermatitis, and infection. When atypical medium or large-sized lymphoid cells are encountered within skin lesions, pathologists should realize these lesions can be ENK/T lymphoma, especially in cases with coexisting tumor necrosis or angioinvasion. A complete evaluation of the upper aerodigestive tract is mandatory to identify the occult primary site of ENK/T lymphoma before establishing primary cutaneous ENK/T lymphoma.

Gamma/Delta (γδ) T Cells: The Role of the T-Cell Receptor in Diagnosis and Prognosis of Hematologic Malignancies

ABSTRACT

There are 2 types of T cells: αβ and γδ T cells, named based on the composition of the T-cell receptor. γδ T cells are rare, making up 0.5%-10% of T cells. Although most leukemias, lymphomas, and immune-mediated conditions derive from αβ T cells, a handful of rare but important diseases are generally derived from γδ T cells, particularly primary cutaneous γδ T-cell lymphoma, hepatosplenic T-cell lymphoma, and monomorphic epitheliotropic intestinal T-cell lymphoma. There are also malignancies that may evince a γδ TCR phenotype, including large granulocytic lymphocyte leukemia, T-cell acute lymphobplastic leukemia (T-ALL), and mycosis fungoides, although such cases are rare. In this article, we will review the genesis of the T-cell receptor, the role of γδ T cells, and the importance of TCR type and methods of detection and outline the evidence for prognostic significance (or lack thereof) in lymphomas of γδ T cells. We will also highlight conditions that rarely may present with a γδ TCR phenotype and assess the utility of testing for TCR type in these diseases.

Primary Cutaneous Gamma-Delta T-Cell Lymphoma Mimicking anaplastic lymphoma kinase-1-Negative Anaplastic Large Cell Lymphoma: A Case Report

ABSTRACT

Primary cutaneous gamma-delta T-cell lymphoma is a rare and aggressive neoplasm, representing less than 1% of all cutaneous T-cell lymphomas. In this article, we report the case of a 49-year-old woman who presented with a history of generalized skin rash and a recent mass on the left upper extremity, as well as right inguinal soft tissue swelling and splenomegaly. Histologic examination of the mass revealed a diffuse subcutaneous infiltrate of large anaplastic and CD30-positive lymphoid cells with rimming of the adipocytes. This case demonstrates unusual cytologic features in primary cutaneous gamma-delta T-cell lymphoma that mimic the features of anaplastic lymphoma kinase-1-negative anaplastic large-cell lymphoma.

Report of Eleven Patients of Subcutaneous Panniculitis-Like T-Cell Lymphoma: Clinicopathologic Features, 18F-FDG PET/CT Findings and Outcome

Objectives

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a fairly rare subtype of primary cutaneous lymphoma. This study aims to investigate the clinicopathologic features, ¹⁸F-FDG PET/CT findings, and outcome of patients with SPTCL.

Methods

A retrospective single-center study enrolled 11 patients with SPTCL between August 2010 and March 2020. A total of 26 ¹⁸F-FDG PET/CT scans were performed, and the initial and follow-up PET/CT imaging features, clinicopathologic and immunohistochemical characteristics, and outcome were analyzed.

Results

The male-to-female ratio was 1.2. The mean age at diagnosis was 24.2 years (age range: 13-48 years). Histopathological examinations revealed atypical T-lymphocyte rimming of individual subcutaneous adipocytes, mostly with CD2⁺, CD3⁺, CD4^-, CD5⁺, CD8⁺, CD56^-, T-cell intracellular antigen-1⁺, Granzyme B⁺, and high Ki-67 index. Multiple large skin ulcerations with a maximum diameter of 10 cm were observed in one of the 11 patients (9.1%, 1/11), and hemophagocytic syndrome was found in another one. At initial PET/CT scans, the lesions in all 11 patients showed increased uptake of ¹⁸F-FDG with a wide range of maximum standard uptake value (SUVmax) from 2.0 to 14.9. The morphology of the lesions presented as multiple nodules and/or disseminated plaques mainly involving the trunk and/or limbs. Five patients had extracutaneous non-lymph node lesions with SUVmax of 5.6 ± 2.8 on ¹⁸F-FDG PET/CT. No significant correlation between SUVmax and Ki-67 index was observed (r = 0.19, P > 0.05). Follow-up ¹⁸F-FDG PET/CT scans in six patients showed complete remission of the disease in two, partial remission in three, and progressive disease in one. During the follow-up period, there was no death except for the patient with multiple ulcerations who died 4 months after diagnosis of SPTCL.

Conclusions

SPTCL may be a group of heterogeneous diseases with varying degrees of ¹⁸F-FDG uptake. ¹⁸F-FDG PET/CT demonstrates its usefulness in detecting disease extent, providing diagnostic work-up, staging, and evaluating treatment response of SPTCL. Multiple large skin ulcerations may be a factor of poor prognosis for patients with SPTCL.

Cutaneous manifestations of lupus erythematosus: A practical clinicopathologic review for pathologists

Accurate diagnosis of connective tissue diseases is often challenging and relies on careful correlation between clinical and histopathologic features, direct immunofluorescence studies, and laboratory workup. Lupus erythematosus (LE) is a prototype of connective tissue disease with a variety of cutaneous and systemic manifestations. Microscopically, cutaneous LE is classically characterized by an interface dermatitis, although other histopathologic patterns also exist depending on the clinical presentation, location, and chronicity of the skin lesions. In this article, we review the clinical, serologic, histopathologic, and direct immunofluorescence findings in LE-specific and LE-nonspecific skin lesions, with an emphasis on lesser known variants, newly described features, and helpful ancillary studies. This review will guide general pathologists and dermatopathologists in accurately diagnosing and subclassifying cutaneous LE.

Clinicopathological and prognostic study of primary cutaneous extranodal natural killer/T-cell lymphoma, nasal type: A systematic review

Comprehensive studies of primary cutaneous extranodal natural killer/T-cell lymphoma (PCENKTL) are scarce. The objectives of this study are to describe PCENKTL in terms of its clinical features, histopathology, immunophenotypes, and prognosis, and to analyze factors affecting patient survival outcomes. We searched four databases and include studies with extractable data. We also searched the Asan Medical Center database for cases of PCENKTL. We include a total of 289 patients. The mean age at diagnosis was 52.8 years and the female to male ratio was 1:1.2. The most common clinical morphology was a subcutaneous nodule, followed by ulceration. About half of the patients presented with disseminated skin lesions. The median overall survival was 12.0 months and the 5-year survival rate was 22.0%. There was no correlation between the clinical morphology or the histopathological features of the skin lesions with the patient outcomes. Advanced TNM stage, a disseminated skin lesion, tumor location on the leg or trunk, the presence of B symptoms, and a high International Prognostic Index score were associated with a worse prognosis, and chemoradiotherapy was associated with a better survival outcome as compared with chemotherapy alone in univariable analyses. In multivariable analyses, only advanced TNM stage and tumor location on the leg were associated with a worse prognosis. In conclusion, PCENKTL is an aggressive cutaneous lymphoma and its prognosis is associated with TNM stage and tumor location.

Primary cutaneous T-cell lymphomas other than Mycosis Fungoides and Sezary Syndrome - Part I: Clinical and histologic features and diagnosis

Primary cutaneous T-cell lymphomas (CTCLs) are defined as lymphomas with a T-cell phenotype that present in the skin without evidence of systemic or extracutaneous disease at initial presentation. CTCLs other than Mycosis Fungoides (MF) and Sézary syndrome (SS) account for approximately one-third of CTCLs and encompass a heterogenous group of non-Hodgkin lymphomas ranging from indolent lymphoproliferative disorders to aggressive malignancies with a poor prognosis. The spectrum of CTCLs continues to broaden as new provisional entities are classified. Given the morphologic and histologic overlap among CTCLs and other diagnoses, a thorough clinical history, physical evaluation, and clinicopathologic correlation are essential in the workup and diagnosis of these rare entities. This article will summarize the epidemiologic, clinical, pathologic, and diagnostic features of CTCLs other than MF and SS.

Primary Cutaneous Gamma-Delta T-Cell Lymphoma With Long-Term Indolent Clinical Course Initially Mimicking Lupus Erythematosus Profundus

Primary Cutaneous Gamma-Delta (γδ) T-Cell Lymphoma (PCGDTCL) is a rare primary cutaneous lymphoma of aggressive nature. Only a few cases with an initially indolent course over years have been published. PCGDTCL can mimic diseases with benign behavior in their clinical and histopathological presentation, such as lupus erythematosus profundus, but also other lymphomas, for example subcutaneous panniculitis-like T-cell lymphoma. In our patient, the results of histopathological, immunofluorescence microscopy, and clinical examinations of early lesions first led to the diagnosis of lupus erythematosus profundus. Two years after this diagnosis and 6 years after the first clinical symptoms appeared, the disease progressed with erosive and ulcerating plaques and a PCGDTCL with hemophagocytic syndrome with an aggressive course was diagnosed. A distinct correlation of clinical, histopathological, immunohistochemical, and molecular-pathological examinations is needed to differentiate between the potentially malignant and benign diseases. Re-biopsies of different skin lesions in uncertain cases are strongly indicated. This case demonstrates that an indolent clinical phenotype can precede an aggressive clinical course in PCGDTCL.

Activated-cytotoxic TCRαβ+CD4+ peripheral T-cell lymphoma with hypodermal localization: Case report of a lymphoproliferative disorder probably evolved from the CD4+ cytotoxic T-cell subpopulation

The World Health Organization (WHO) classification of hematopoietic and lymphoid tumors identifies distinctive subtypes of peripheral T-cell lymphoma (PTCL), and, additionally, some PTCLs involving mostly extranodal sites like the skin. The difficulty of classifying PTCLs according to the normal stages of T-cell differentiation and the lack of definitive diagnostic markers for most of the subtypes make the diagnosis of these diseases challenging. PTCL cases which do not fit into any of the specifically defined entities are categorized as PTCL not otherwise specified (PTCL-NOS). PTCLs-NOS represent less than 2% of the total cases of T-cell lymphoma involving the skin. This article illustrates a case of a PTCL-NOS in which tumor cells have an activated cytotoxic TCRαβ+CD3+CD4+CD56+ T-cell phenotype and histopathologic features of subcutaneous panniculitis-like T-cell lymphoma, leading to a fatal outcome.

Panniculitis-like T-cell-lymphoma in the mesentery associated with hemophagocytic syndrome: autopsy case report

Background

Panniculitis-like T-cell lymphoma is an uncommon type of non-Hodgkin lymphoma, occurring usually in the form of nodules within the subcutaneous fat tissue of the extremities or trunk. In the literature, subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is described as a distinct type of T-cell lymphoma with a variable clinical behavior, depending on molecular phenotype of T-cell receptor (TCR) and on the presence or absence of hemophagocytic syndrome.

Case presentation

We present a bioptic and autoptic case of a 65-years old Caucasian man with panniculitic T-cell lymphoma with morphological and immunohistochemical features of SPTCL, limited to the retroperitoneal and mesenteric mass, i.e. without any cutaneous involvement, and associated with severe hemophagocytic lymphohistiocytosis.

Conclusion

A panniculitic T-cell lymphoma with morphological and molecular features of SPTCL, which is limited to mesentery, i.e. does not involve subcutaneous fat, seems to be exceedingly rare.

Blastic Plasmacytoid Dendritic Cell Neoplasm: State of the Art and Prospects

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare tumour, which usually affects elderly males and presents in the skin with frequent involvement of the bone-marrow, peripheral blood and lymph nodes. It has a dismal prognosis, with most patients dying within one year when treated by conventional chemotherapies. The diagnosis is challenging, since neoplastic cells can resemble lymphoblasts or small immunoblasts, and require the use of a large panel of antibodies, including those against CD4, CD56, CD123, CD303, TCL1, and TCF4. The morphologic and in part phenotypic ambiguity explains the uncertainties as to the histogenesis of the neoplasm that led to the use of various denominations. Recently, a series of molecular studies based on karyotyping, gene expression profiling, and next generation sequencing, have largely unveiled the pathobiology of the tumour and proposed the potentially beneficial use of new drugs. The latter include SL-401, anti-CD123 immunotherapies, venetoclax, BET-inhibitors, and demethylating agents. The epidemiologic, clinical, diagnostic, molecular, and therapeutic features of BPDCN are thoroughly revised in order to contribute to an up-to-date approach to this tumour that has remained an orphan disease for too long.

New Therapies and Immunological Findings in Cutaneous T-Cell Lymphoma

Primary cutaneous lymphomas comprise a group of lymphatic malignancies that occur primarily in the skin. They represent the second most common form of extranodal non-Hodgkin’s lymphoma and are characterized by heterogeneous clinical, histological, immunological, and molecular features. The most common type is mycosis fungoides and its leukemic variant, Sézary syndrome. Both diseases are considered T-helper cell type 2 (Th2) diseases. Not only the tumor cells but also the tumor microenvironment can promote Th2 differentiation, which is beneficial for the tumor cells because a Th1 environment enhances antitumor immune responses. This Th2-dominant milieu also underlies the infectious susceptibility of the patients. Many components, such as tumor-associated macrophages, cancer-associated fibroblasts, and dendritic cells, as well as humoral factors, such as chemokines and cytokines, establish the tumor microenvironment and can modify tumor cell migration and proliferation. Multiagent chemotherapy often induces immunosuppression, resulting in an increased risk of serious infection and poor tolerance. Therefore, overtreatment should be avoided for these types of lymphomas. Interferons have been shown to increase the time to next treatment to a greater degree than has chemotherapy. The pathogenesis and prognosis of cutaneous T-cell lymphoma (CTCL) differ markedly among the subtypes. In some aggressive subtypes of CTCLs, such as primary cutaneous gamma/delta T-cell lymphoma and primary cutaneous CD8⁺ aggressive epidermotropic cytotoxic T-cell lymphoma, hematopoietic stem cell transplantation should be considered, whereas overtreatment should be avoided with other, favorable subtypes. Therefore, a solid understanding of the pathogenesis and immunological background of cutaneous lymphoma is required to better treat patients who are inflicted with this disease. This review summarizes the current knowledge in the field to attempt to achieve this objective.

NK/T-cell lymphoma, nasal type, γδ T-cell lymphoma, and CD8-positive epidermotropic T-cell lymphoma-clinical and histopathologic features, differential diagnosis, and treatment

The cytotoxic lymphomas of the skin constitute a heterogeneous group of rare lymphoproliferative diseases that are derived from mature T cells and natural killer (NK) cells that express cytotoxic molecules (T-cell intracellular antigen- 1, granzyme A/B, and perforin). Although frequently characterized by an aggressive course and poor prognosis, these diseases can have variable clinical behavior. This review delivers up-to-date information about the clinical presentation, histopathologic features, differential diagnosis, and therapy of extranodal NK/T-cell lymphoma, nasal type, primary cutaneous gamma delta T-cell lymphoma, and primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma.

Classification and Treatment of Rare and Aggressive Types of Peripheral T-Cell/Natural Killer-Cell Lymphomas of the Skin

Background

The classification of cutaneous lymphomas has been contentious. Two major competing classifications were the World Health Organization (WHO) and the European Organization for Research and Treatment of Cancer (EORTC). The principal authors met for a consensus meeting resulted in a combined classification called WHO-EORTC Classification of Cutaneous Lymphoma.

Methods

We review the classification of “mature” or peripheral T-cell lymphoma (PTCL) with high predilection to the skin as published by the WHO-EORTC. We also highlight new information and changes from the previous classifications of cutaneous PTCL according to the WHO classification or the EORTC classification. Finally, the salient findings are compared with similar-looking nodal PTCLs with a high frequency of skin involvement.

Results

This review focuses on a rare group of cutaneous PTCLs other than mycosis fungoides or its variants. Changes from the previous classifications are discussed, and the rare group of nodal PTCLs with high predilection to the skin are presented. The salient findings, diagnostic features, and treatments are included, along with summary tables and clinical-histopathologic images.

Conclusions

This review may serve as a guide for hematologists, oncologists and dermatologists in the diagnosis and management of these rare, aggressive, and often difficult to diagnose lymphomas. Although cutaneous lymphomas are morphologically identical to systemic lymphomas, the former behave differently, require divergent management, and should be recognized as separate entities. The consensus WHO-EORTC classification presents unified terminology and definitions to promote conformity in diagnosing and treating these cases, to foster a multidisciplinary approach to these often-obscure diseases, and to lead to more advances in identifying molecular targets specific to these entities.

Epstein-Barr Virus-associated Lymphoproliferative Disorders in the Skin

Epstein-Barr virus (EBV)-associated lymphoproliferations involving the skin are a rare but important group of diseases with a broad spectrum of behavior, ranging from self-limiting spontaneously resolving disorders to highly aggressive malignancies. They may be of B, T, or natural killer (NK) cell type and include EBV-positive mucocutaneous ulcer, lymphomatoid granulomatosis, EBV-positive diffuse large B-cell lymphoma, hydroa vacciniforme-like lymphoproliferative disorder, and extranodal NK/T-cell lymphoma of nasal type. Recognition and distinction of these entities is important in view of their differing prognoses and treatments. An association with EBV may be the first indication that a patient is immunosuppressed.

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.

Primary Cutaneous Lymphomas in Children and Adolescents

Primary cutaneous lymphomas are rare in children and mostly represented by mycosis fungoides and CD30(+) lymphoproliferative disorders. Most pediatric cutaneous lymphomas have similar clinical/pathological features as their adult counterparts, particularly the T-cell subtypes. With regard to outcome, adult cutaneous mature T-cell lymphomas have a tendency to progression, while this appears to be relatively infrequent in children. The outcome of cutaneous B-cell lymphomas depends on subtype, with the B-lymphoblastic entity being associated with similar outcomes to precursor B acute lymphoblastic leukemia, while there are insufficient data on other entities. The diagnosis and treatment of these patients require a close collaboration between experienced pediatric pathologists, dermatologists, and oncologists. Prospective collection of longitudinal clinical and biological data from children with these rare lymphomas is needed to better understand their biological and clinical behavior and to ultimately discover the best therapeutic strategies.

Clinical manifestations and pathogenesis of cutaneous lymphomas: current status and future directions

The primary cutaneous lymphomas are a heterogeneous group of T-, Natural Killer- and B- cell neoplasms with a wide range of clinical and pathological presentations, and with very different prognoses compared to systemic lymphomas. Recent studies have shown that the skin microenvironment, which is composed of various immune cell subsets as well as their spatial distribution and T-cell interactions through different chemokines and cytokines, has an important role in the development and pathogenesis of cutaneous lymphomas and has assisted in the development of novel and more effective immunotherapies. The following review will focus on the major subtypes of primary cutaneous lymphomas, including the clinical and histological patterns, molecular hallmarks, and current and future treatment strategies.

Case report of subcutaneous panniculitis-like T-cell lymphoma complicated by eyelid swelling

BACKGROUND

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare, highly malignant, extranodal lymphoma that preferentially infiltrates into subcutaneous adipose tissue. No case of SPTCL with the earliest symptoms occurring in the eye region has been reported. We report a case of SPTCL complicated by eyelid swelling.

CASE PRESENTATION

A 19-year-old Japanese man presented with worsening left eyelid swelling. The patient's best-corrected visual acuity (BCVA) was 0.8, left intraocular pressure was 36 mm Hg, and he had prominent mucosal hyperemia and edema. His left eye had light reflex attenuation and a positive relative afferent pupillary defect, but no abnormality in the visual field or central flicker value. Magnetic resonance imaging showed left orbital adipose tissue inflammation. The blood examination was normal. He was hospitalized for an intensive examination and treatment for possible cellulitis, orbital panniculitis, and inflammatory pseudotumor. Systemic antibiotics were initiated. The following day, he underwent a sub-Tenon's injection of triamcinolone. Left eyelid swelling gradually improved. He was discharged on the ninth day and followed up with oral prednisolone. Two months later, he visited our department because of a high fever and slight right eyelid swelling. Ocular hypertension was detected. A blood examination revealed pancytopenia. Computed tomography showed fluid retention, hydrothorax, and abdominal dropsy. Magnetic resonance imaging revealed right orbital panniculitis. Because of suspected hemodyscrasia, he was referred to the hematology department of another hospital where he was diagnosed with SPTCL.

CONCLUSIONS

The possibility of SPTCL, with attention to recurrence and systemic symptoms, should be considered in young patients with sudden eyelid swelling.

Neoplasms derived from plasmacytoid dendritic cells

Plasmacytoid dendritic cell neoplasms manifest in two clinically and pathologically distinct forms. The first variant is represented by nodular aggregates of clonally expanded plasmacytoid dendritic cells found in lymph nodes, skin, and bone marrow ('Mature plasmacytoid dendritic cells proliferation associated with myeloid neoplasms'). This entity is rare, although likely underestimated in incidence, and affects predominantly males. Almost invariably, it is associated with a myeloid neoplasm such as chronic myelomonocytic leukemia or other myeloid proliferations with monocytic differentiation. The concurrent myeloid neoplasm dominates the clinical pictures and guides treatment. The prognosis is usually dismal, but reflects the evolution of the associated myeloid leukemia rather than progressive expansion of plasmacytoid dendritic cells. A second form of plasmacytoid dendritic cells tumor has been recently reported and described as 'blastic plasmacytoid dendritic cell neoplasm'. In this tumor, which is characterized by a distinctive cutaneous and bone marrow tropism, proliferating cells derive from immediate CD4(+)CD56(+) precursors of plasmacytoid dendritic cells. The diagnosis of this form can be easily accomplished by immunohistochemistry, using a panel of plasmacytoid dendritic cells markers. The clinical course of blastic plasmacytoid dendritic cell neoplasm is characterized by a rapid progression to systemic disease via hematogenous dissemination. The genomic landscape of this entity is currently under intense investigation. Recurrent somatic mutations have been uncovered in different genes, a finding that may open important perspectives for precision medicine also for this rare, but highly aggressive leukemia.

Primary cutaneous T-cell lymphomas: a review

Primary cutaneous T-cell lymphomas (CTCLs) represent a number of extranodal lymphomas arising from a malignant population of lymphocytes in the skin, with the most common type being mycosis fungoides (MF) representing half of all primary CTCLs. Despite advances in immunohistochemistry and molecular methodology, significant diagnostic challenges remain due to phenotypic overlap of primary CTCLs with several inflammatory dermatoses, secondary lymphomas, among other conditions. Clinical features such as presentation and morphology, staging, histology, immunophenotype and molecular features must be considered in detail before a diagnosis is made in order to minimise false-positive, false-negative and indeterminate diagnoses. Herein, we review primary CTCLs, including epidemiological data, a brief summary of clinical presentations, immunophenotype, molecular signatures and differential diagnoses.

Primary cutaneous lymphomas: diagnosis and treatment

Primary cutaneous lymphomas (CLs) are a heterogeneous group of lymphoproliferative neoplasms, with lymphatic proliferation limited to the skin with no involvement of lymph nodes, bone marrow or viscera at the diagnosis. Cutaneous lymphomas originate from mature T-lymphocytes (65% of all cases), mature B-lymphocytes (25%) or NK cells. Histopathological evaluation including immunophenotyping of the skin biopsy specimen is the basis of the diagnosis, which must be complemented with a precise staging of the disease and identification of prognostic factors, to allow for the choice of the best treatment method as well as for the evaluation of the treatment results.

Primary cutaneous lymphoma in southern Brazil: a 12-year single-center experience

BACKGROUND

Primary cutaneous lymphomas (PCL) are a group of extranodal non-Hodgkin lymphomas presenting with no evidence of extracutaneous disease at the time of diagnosis. Few longitudinal studies of PCL have been conducted, particularly in South American populations. Our objective was to describe the behavior of PCL and evaluate patient survival in a cohort of patients from southern Brazil.

METHODS

We conducted a retrospective cohort study of all patients with a histopathological diagnosis of PCL receiving care at a tertiary referral center in southern Brazil from 2000 to 2012. Clinical, laboratory, and histopathological data, treatment variables, and survival curves were analyzed.

RESULTS

Eighty-nine patients with PCL were included, with a mean age at diagnosis of 58.9 years. Cutaneous T-cell and natural killer (NK) cell lymphomas (CTCL/NKCL) accounted for 78.4% of cases and cutaneous B-cell lymphomas (CBCL) for 21.6%; 57.4% of patients with CTCL/NKCL and 50% of patients with CBCL were male. Half of all cases were mycosis fungoides (MF). The 5-year survival rate was 74.8% for MF, 61% for Sézary syndrome, 87.5% for primary cutaneous CD30+ lymphoproliferative disorders, and 88.9% for primary cutaneous follicle center lymphoma.

CONCLUSIONS

In this cohort of patients with PCL from southern Brazil, CTCL/NKCL was more prevalent than CBCL, and the MF subtype was predominant. Survival curves were similar to those reported in the literature, except for Sézary syndrome, which had a better prognosis in this sample.

Gamma-delta T-cell lymphoma arising in a long-standing cutaneous plaque

The precise classification and characterization of primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) has been hindered by clinical and morphologic features that overlap with other lymphomas, especially subcutaneous panniculitis-like T cell lymphoma (SPTCL). The recent World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification distinguishes the more aggressive PCGD-TCL from the usually indolent SPTCL, however. We report a 30-year-old woman with an indurated violaceous plaque on the left cheek that had been present for several years. Biopsies showed a dense lymphocytic infiltrate involving the subcutis and dermis that consisted mostly of small and medium-sized lymphocytes, some with irregular nuclear contours and dense chromatin. These cells were positive for TIA-1, TCR-gamma and CD8, but negative for beta-F1 and granzyme-B. Staging with positron emission tomography-computed tomography (PET/CT), CBC and bone marrow with flow cytometry identified lymphadenopathy as well as blood and marrow involvement by an abnormal TCRgd-positive T-cell proliferation (Ann Arbor Stage IV). The patient's history of a long-standing lesion in this case is unusual, in that gamma-delta T-cell lymphomas are typically rapidly progressive neoplasms. As such, it raises the possibility of 'transformation' of a long-standing inflammatory process into an overt lymphoma.

Successful treatment of disseminated subcutaneous panniculitis-like T-cell lymphoma with single agent oral cyclosporine as a first line therapy

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is a rare cutaneous neoplasm of mature cytotoxic T-cells. Currently there are no standardized therapies for SPTL; however good responses have been seen with chemotherapy regimens generally employed for B-cell lymphomas. Cyclosporine, an immunosuppressant, has shown good responses in relapsed/refractory SPTL; however its use in first line setting is not well established. We, herein, describe a 22-year-old girl with disseminated SPTL who attained complete clinical remission with single agent oral cyclosporine used as a first line therapy.

Phenotypic variability in primary cutaneous anaplastic large T-cell lymphoma: a study on 35 patients

Primary cutaneous anaplastic large T-cell lymphoma (pcALCL) is a well-defined entity characterized by neoplastic cells expressing CD30, CD2, CD3, CD4, and CD5. Cases with different phenotype have been reported, including variable loss of CD2, CD3, and CD5, and expression of cytotoxic phenotype (CD8⁺) and/or of cytotoxic proteins. Aberrant phenotypes represent a diagnostic pitfall and may be the cause of misdiagnoses. We reviewed 35 cases of pcALCL (M:F = 19:16; mean age, 50.8 years; range, 14-92 years), to better characterize the immunophenotypic spectrum of the disease. Twelve cases (34%) had a T-helper phenotype (CD4⁺/CD8⁻), and TIA-1 was positive in 5 of 8 stained cases. Six cases (18%) had a T-cytotoxic phenotype (CD4⁻/CD8⁺) and were also positive for TIA-1. Positivity for both CD4 and CD8 was observed in 7 cases (20%), 4 of which were stained for TIA-1 and found to be positive, whereas both CD4 and CD8 were negative in 9 cases (26%, only 1/8 tested cases being TIA-1 positive). CD2 was positive in 21 of 27 tested cases (78%), CD3 in 21 of 34 cases (62%), and CD5 in 15 of 31 cases (48%). Interestingly, 11 cases (31%) showed a profoundly aberrant phenotype lacking simultaneously several T-cell markers. Our data allow a better characterization of pcALCL with aberrant phenotypes, showing the remarkable variability in expression of different markers.

CD30-Negative Cutaneous T-Cell Lymphomas Other than Mycosis Fungoides

Cutaneous T-cell lymphomas (CTCLs), other than mycosis fungoides/Sézary syndrome and the group of cutaneous CD30(+) lymphoproliferative disorders, are rare. These include subcutaneous panniculitis-like T-cell lymphoma (SPTCL); extranodal natural killer/T-cell lymphoma, nasal type; primary cutaneous peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS); and rare subtypes of PTCL, NOS. Apart from SPTCL and primary cutaneous CD4-positive small-medium pleomorphic T-cell lymphoma, these lymphomas have in common aggressive clinical behavior and poor prognosis. Differentiation between these different types of CTCL may be difficult and requires integration of histopathologic findings with clinical data and the results of phenotypic and often molecular genetic studies.

Subcutaneous panniculitis-like T-cell lymphoma in a case of carcinoma cervix

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an uncommon extra nodal non-Hodgkin lymphoma accounting for less than 1% of all NHLs known to have an aggressive course, with no well-defined treatment protocols. A 42-year-old lady, operated five months earlier for a squamous cell carcinoma of the cervix presented with pain and induration of the lower part of the anterior abdominal wall; 3 months after completing chemotherapy and radiotherapy. FNAC done, yielded scanty material and was inconclusive. The biopsy showed features of a subcutaneous panniculitis-like T-cell lymphoma. While on chemotherapy she developed a vault recurrence and extensive intra-abdominal spread of the squamous cell carcinoma and succumbed. SPTCL is a rare entity and has been reported in renal and cardiac allograft recipients and in one case of ovarian carcinoma. Its occurrence in the setting of carcinoma cervix is unusual, hence is being reported.

Non Hodgkin T cell lymphoma: an atypical clinical presentation

Cytotoxic lymphomas comprise a spectrum of peripheral T-cell lymphomas that can have a initial or late cutaneous presentation. We describe a 46-year-old man from Cape Verde, with a dermatosis involving his face and trunk, consisting of monomorphic papules with a smooth surface and both motor and sensory polyneuropathy.The hypothesis of leprosy was supported by the clinical and initial hystopathological findings and the patient was referred to our hospital with suspected Hansen's disease. In the new skin and lymph node biopsies a lymphocyte population was identified whose immunohystochemistry study allowed the diagnosis of T-cell lymphoma with expression of cytotoxic markers. The patient was started on chemotherapy with initial remission of the skin lesions but, subsequently, progression of systemic disease.

The presenting manifestations of subcutaneous panniculitis-like T-cell lymphoma and T-cell lymphoma and cutaneous γδ T-cell lymphoma may mimic those of rheumatic diseases: a report of 11 cases

This study aims to investigate the association between subcutaneous panniculitis-like T-cell lymphoma (SPTCL) or cutaneous gamma/delta T-cell lymphoma (CGDTCL) and a variety of manifestations that mimic autoimmune disorders. A retrospective chart review was made for 11 patients who were initially diagnosed as autoimmune diseases but finally turned out to be SPTCL or CGDTCL. Eleven patients were initially diagnosed with erythema nodosum, nodular panniculitis, lupus erythematosus profundus, systemic vasculitis, dermatomyositis, or pyoderma gangrenosum. The interval between presenting symptoms and the diagnosis of lymphoma was 17.5 (range, 3-84)  months on average. Nearly all cases had multiple subcutaneous nodules or plaques that were most commonly distributed on the extremities and trunk. Fever was the primary accompanying sign (9/10), followed by lymphadenopathy (6/11), splenomegaly (5/11), and hepatomegaly (3/11). Two patients developed hemophagocytic syndrome. A total of 26 biopsies involving multiple anatomic locations were performed. Antirheumatic therapy including steroids and immunosuppressive agents administered before the identification of T-cell lymphoma revealed unsustainable therapeutic effect. In contrast, seven cases gained partial response after chemotherapy, while the remaining four cases died with disease progression and disease-associated severe infections. SPTCL and CGDTCL are rare and heterogeneous which may resemble those rheumatologic diseases that are characterized by inflammation involving the skin or subcutaneous fat tissue. The diagnosis relies on the constellation of disease-specific pathologic, immunophenotypic, and T-cell receptor gene rearrangement tests. In the context of an ambiguous clinical picture demonstrating inconsistency with the initial diagnosis of benign autoimmune diseases, repeated excisional biopsies of the subcutaneous lesions may be required to uncover the underlying lymphoma.