Primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma: Proposed diagnostic criteria and therapeutic evaluation

Prominent tissue hemophagocytic lymphohistiocytosis obscuring primary cutaneous gamma/delta (γδ) T-cell lymphoma

Primary cutaneous gamma/delta (γδ) T-cell lymphoma (PCGDTCL) is a rare, aggressive malignant neoplasm of γδ T lymphocytes arising within the skin and subcutis. We present a challenging case of PCGDTCL diagnosed in a 35-year-old male soldier who presented with constitutional symptoms, pancytopenia, hemophagocytic lymphohistiocytosis (HLH), disseminated lymphadenopathy, and cutaneous lesions on his extremities and back following a deployment to Iraq and Syria. Histopathologic evaluation of an excisional biopsy showed that PCGDTCL can be focal, localized to the subcutaneous adipose tissue, and obscured by predominant HLH in the surrounding tissues. Pathologists should recognize that the diagnosis of PCGDTCL may be confounded by florid HLH and require multiple biopsies and a comprehensive immunohistochemical panel.

Clinical and Histologic Variants of CD8+ Cutaneous T-Cell Lymphomas

Although the vast majority of CTCL subtypes are of the CD4+ T-helper cell differentiation phenotype, there is a spectrum of CD8+ variants that manifest wide-ranging clinical, histologic, and phenotypic features that inform the classification of the disease. CD8, like CD4, and cytotoxic molecules (including TIA and granzyme) are readily detectable via IHC staining of tissue and, when expressed on the phenotypically abnormal T-cell population, can help distinguish specific CTCL subtypes. Nonetheless, given that the histopathologic differential for CD8+ lymphoproliferative disorders and lymphomas may range from very indolent lymphomatoid papulosis (LyP) to aggressive entities like CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (AECTCL), CD8 and/or cytotoxic molecule expression alone is insufficient for diagnosis and is not in itself an indicator of prognosis. We present a review of CTCL subtypes that can demonstrate CD8 positivity: CD8+ mycosis fungoides (MF), LyP type D, subcutaneous panniculitis-like T-cell lymphoma (SPTCL), primary cutaneous gamma/delta T-cell lymphoma (PCGDTL), CD8+ AECTCL, and acral CD8+ T-cell lymphoproliferative disorder (acral CD8+ TCLPD). These diseases may have different clinical manifestations and distinctive treatment algorithms. Due to the rare nature of these diseases, it is imperative to integrate clinical, histologic, and immunohistochemical findings to determine an accurate diagnosis and an appropriate treatment plan.

Chronic Radiation Dermatitis Secondary to Narrow-Band Ultraviolet B Therapy in a Patient With Primary Cutaneous CD8 + T-Cell Lymphoma With Cytotoxic Granules

ABSTRACT

Conventional therapies for CD8 + cutaneous T-cell lymphoma include topical steroids, topical nitrogen mustard, topical bexarotene, ultraviolet B therapy, psoralen and ultraviolet A therapy, local radiotherapy, and interferon alfa; however, these treatments are often found to be ineffective. Presented is a case of CD8 + cutaneous T-cell lymphoma with near-complete response to narrow-band ultraviolet therapy because of chronic radiation dermatitis initially believed to be possible progression of a CD8 + cutaneous epidermotropic cytotoxic T-cell lymphoma.

Probable Primary Cutaneous CD8+ Aggressive Epidermotropic Cytotoxic T-cell Lymphoma: A Case Report of a Diagnostic Challenge

Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma is a rare variety of cutaneous lymphoma. This subtype has an aggressive and quickly progressive clinical course with a survival time of 32 months from the commencement of skin lesions. This article describes a probable case of primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma in a 63-year-old female, which manifested as diffuse non-pruritic erythematous plaques and nodules. The diagnosis of this possible entity was aided by the histopathological and immunohistochemical findings, while immunohistochemistry for T-cell receptor (TCR) gamma/delta could not be done.

Rapidly Progressive Multiple Skin Plaques and Nodules: A Quiz

Abstract is missing (Quiz)

Nasolabial Ulcerated Placard Revealing a Primary Cutaneous Aggressive Epidermotropic CD8+ T-cell Lymphoma

Primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma is a rare entity representing less than 1% of cutaneous lymphomas. It has an aggressive clinical manifestation with a poor prognosis. It is characterized by cytotoxic and epidermotropic CD8+ proliferation. It also expresses the TIA-1 marker. We report a new case for its display and aggressive character, diagnostic difficulty, and good therapeutic response to chemotherapy. This is a 62-year-old female patient admitted to the hospital for a nasolabial ulcerated placard evolving for two years. Clinical examination revealed submandibular lymph nodes. The specimen analysis associated with anatomoclinical manifestation was concluded for a primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma. Tumor extent assessment did not show any secondary localization. The blood tests and serology were unremarkable. The patient had benefited from a CHOEP-type multidrug therapy protocol with complete healing of the lesion after three courses of chemotherapy.

Chidamide combined with traditional chemotherapy for primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma: A case report

BACKGROUND

Traditional chemotherapy has benefited many patients with non-Hodgkin's lymphoma, but results in a very poor response in patients with rare lymphomas or refractory lymphomas. Previous studies have shown that chidamide has potential anti-lymphoma activity and reverses lymphoma cell chemoresistance to increase the chemosensitivity of lymphoma cells to traditional chemotherapy.

CASE SUMMARY

A 14-year-old boy was admitted to our hospital with a 5-d history of generalized erythema, papules, and blisters. Initially, the disease was refractory to potent anti-allergic and anti-infective treatment, and his condition progressively worsened. Skin biopsy revealed primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma. Considering that the disease is extremely rare in clinical practice, existing case reports have shown poor efficacy with traditional chemotherapy alone. We recommend chidamide combined with traditional chemotherapy for treatment. The regimen was as follows: Chidamide 30 mg/biw, cyclophosphamide 1100 mg/d1, pirarubicin 70 mg/d1, vincristine 2 mg/d1, dexamethasone 20 mg/d1-5, etoposide 100 mg/d1-5, in a 21 d cycle. The treatment effect was considerable, and complete remission was achieved after 4 cycles of treatment, after which the patient completed a total of 6 cycles of treatment. Subsequently, the patient regularly took chidamide 20 mg/biw as maintenance therapy for 1 year. To date, the patient has been disease-free for 3 years.

CONCLUSION

This case suggests that the combination of chidamide and traditional chemotherapy is effective in primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma.

CD8+ mycosis fungoides with ichthyosiform clinical presentation and angiocentric feature

Mycosis fungoides (MF) is characterized by epidermotropic atypical lymphocytes infiltrate with α/β T-helper memory immunophenotype (βF1+, CD3+, CD4+, CD45Ro+, and CD8-). Angiocentricity is always associated with aggressive behavior or poor outcome in primary or secondary cutaneous lymphomas. Rare cases of angiocentric MF with a T-cytotoxic immunophenotype (CD3+, CD4-, CD8+, TIA-1+) have been described. Here, we report a 27-year-old man diagnosed with MF, clinically presenting with ichthyosiform lesions on his trunk and limbs. Biopsy demonstrated a CD3+ and CD8+ atypical lymphocytic infiltrate with marked epidermotropism and angiocentricity. Awareness of this rare MF variant with unusual clinicopathological characteristics is important to avoid misdiagnosis.

Long-Term Remission After Matched Sibling Donor Hematopoietic Cell Transplantation in a Patient With Primary Cutaneous CD8+ Aggressive Epidermotropic Cytotoxic T-Cell Lymphoma

Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (CD8+ PCAECTL) is an extremely rare neoplasm with a poor prognosis. Chemotherapy typically does not result in a sustained response, and hematopoietic stem cell transplant (HSCT) is the only therapy that has been shown to produce a durable response of any kind. Here, we report a case of a 25-year-old previously healthy male who presented with a painful ulcerative lesion on the bottom of his right great toe and local lymphadenopathy. The biopsy of the lesion was consistent with CD8+ PCAECTL. He received immediate chemotherapy followed by matched related donor HSCT (MRD-HSCT) and remained in complete remission (CR) for eight years post-transplant, longer than any CR reported in the literature. In conclusion, our report provides clinical evidence that early transplant consult and donor search is one of the key factors in the management of CD8+ PCAECTL.

Vulvar Primary Cutaneous CD8+ Aggressive Epidermotropic Cytotoxic T-Cell Lymphoma

Cutaneous T-cell lymphomas may present with a clinical course that is incongruent with the associated histologic findings. Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma classically presents as an abrupt eruption of disseminated ulcerated annular plaques with aggressive behavior and a poor prognosis. Herein we describe a vulvar primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma with a locally aggressive clinical course that was strikingly responsive to radiation therapy. As aggressive therapy involving systemic chemotherapy is indicated for primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, appropriate clinico-pathologic correlation is crucial for preventing potentially excessive or insufficient therapeutic intervention. Our case also highlights the pivotal role of both radiation therapy and infection control in the management of aggressive cutaneous vulvar lymphomas.

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.

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.

High incidence of adnexotropism in cytotoxic cutaneous lymphomas

BACKGROUND

Primary cutaneous gamma-delta T-cell lymphoma (PCγδTCL) and primary cutaneous aggressive epidermotropic T-cell lymphomas (PCAETCL) are rare aggressive cytotoxic cutaneous lymphomas (CyCL) often difficult to diagnose. Histopathologically, PCAETCL and PCγδTCL may resemble mycosis fungoides (MF) and the presence of adnexotropism in CyCL (CyCL) contributes to this diagnostic challenge, especially in the setting of atypical and double-negative phenotypes.

METHODS

In this retrospective study clinical data and histopathological section of 91 patients were analyzed for signs of clinical and histopathological signs adnexotropism.

RESULTS

Adnexotropism was identified in 48.4% (44/91) of cases, including PCAETCL (40.9%, 18/44), PCγδTCL and cytotoxic cutaneous lymphomas, not otherwise specified (CyCTCL, NOS) (43.2%, 19/44 and 15.9%, 7/44). Comparison between disease-related mortality with Kaplan-Meier survival analysis of non-adnexotropic vs adnexotropic CyCL did not show any significant difference between the two groups (P = 0.8). Clinically they present with patches, plaques, and tumors and commonly with ulceration, but follicular prominence or alopecia are rare. Clinical signs of adnexotropism such as alopecia and hypo- or anhidrosis were rarely seen.

CONCLUSION

Adnexotropism is a common finding in CyCL, especially in PCAETCL. Adnexotropic CyCL may be histopathologically difficult to distinguish from folliculotropic mycosis fungoides. A comprehensive IHC panel should be routinely performed in such cases.

[Facial ulcerated nodules revealing primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma]

BACKGROUND

Primary cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma is a rare disease with a poor prognosis. Herein we report a new case, with facial lesions, which was difficult to diagnose.

PATIENTS AND METHODS

A 39-year-old woman was hospitalized for ulcerated nodules on the face that had been developing rapidly for 8 weeks. She had visited Djerba, Tunisia, 3 months earlier. No abnormalities were found on previous routine blood tests. Histopathological analysis of a skin biopsy had revealed non-specific lymphocytic infiltrate. Various therapies, including amoxicillin/clavulanic acid, valaciclovir, corticosteroids, colchicine and doxycycline, proved ineffective. Screening of the cutaneous sample for leishmaniasis proved positive using PCR but negative by direct examination and culture. Treatment was initiated with meglumine antimoniate. A further cutaneous biopsy revealed diffuse lymphocytic proliferation and led to a diagnosis of cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma. A PET scan showed multiple sites of hypermetabolism affecting the face and lymph nodes. Meglumine antimoniate was stopped and the patient experienced complete remission after chemotherapy.

CONCLUSION

Ulcerated nodules with acute progression on acral sites are characteristic of cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma. In our case, the positive result of PCR screening for Leishmania that was ultimately considered a false positive was a confounding factor in the diagnostic process. Regarding therapy, aggressive treatment strategies such as multiagent chemotherapy and hematopoietic stem-cell transplantation are needed due to the rapid progression of the lymphoma.

Cutaneous T Cell Lymphoma: A Difficult Diagnosis Demystified

Cutaneous T cell lymphoma (CTCL) represents a heterogeneous group of extranodal non-Hodgkin lymphomas in which monoclonal T lymphocytes infiltrate the skin. The mechanism of CTCL development is not fully understood, but likely involves dysregulation of various genes and signaling pathways. A variety of treatment modalities are available, and although they can induce remission in most patients, the disease may recur after treatment cessation. Owing to relatively low incidence and significant chronicity of disease, and the high morbidity of some therapeutic regimens, further clinical trials are warranted to better define the ideal treatment option for each subtype of CTCL.

Interferon alfa-2a maintenance after salvage autologous stem cell transplantation in atypical mycosis fungoides with central nervous system involvement

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma with unfavourable prognosis for patients with advanced stages of the disease. Refractory disease and advanced-stage disease require systemic therapy. We report on a rare case of an atypical predominantly CD8⁺ folliculotropic MF, a subtype of MF with poorer prognosis, in a 59-year-old woman. She was initially diagnosed with MF restricted to the skin, of T3N0M0B0/stage IIB according to the current World Health Organization-European Organisation for Research and Treatment of Cancer classification. First-line treatment with local percutaneous radiotherapy in combination with systemic interferon alfa-2a resulted in complete remission. However, 21 months later the disease progressed to T3N0M1B0/stage IVB with development of cerebral manifestation and thus very poor prognosis. Allogeneic stem cell transplantation (SCT) was not a therapeutic option due to the lack of a suitable donor. We initiated methotrexate and cytarabine chemotherapy, followed by high-dose chemotherapy with thiotepa and carmustine with autologous SCT. Despite rapid response and complete remission of the cerebral lesions, disease recurrence of the skin occurred soon after. Interestingly, readministration of interferon alfa-2a as a maintenance treatment after the salvage autologous SCT resulted in a durable complete remission during the follow-up period of currently 17 months after autologous SCT. What's already known about this topic? Mycosis fungoides is a primary cutaneous T-cell lymphoma with unfavourable prognosis for the advanced stages of the disease. A refractory course of disease requires systemic therapy. What does this study add? We report on an unusual case of a patient with mycosis fungoides with cerebral involvement, in which a durable complete remission was achieved upon autologous stem cell therapy and interferon alfa-2a maintenance therapy.

Cutaneous Lymphoproliferative Disorders: What's New in the Revised 4th Edition of the World Health Organization (WHO) Classification of Lymphoid Neoplasms

Cutaneous lymphoproliferative disorders remain a challenging aspect of dermatopathology, in part due to the rarity of the entities and extreme variability in clinical outcomes. Although many of the entities remain unchanged, the approach to some of them has changed in the new 2016 classification scheme of the World Health Organization. Chief among these are Epstein-Barr virus-associated lymphoproliferative disorders such as Epstein-Barr virus-associated mucocutaneous ulcer and hydroa vacciniforme-like lymphoproliferative disorder, primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, primary cutaneous acral CD8+ T-cell lymphoma, primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder, and breast implant-associated anaplastic large cell lymphoma. In addition, translocations and gene rearrangements such as those involving the 6p25.3 locus have started to inform diagnosis and classification of anaplastic large cell lymphoma and lymphomatoid papulosis. In this review, we will examine what is new in the diagnostic toolbox of cutaneous lymphoproliferative disorders.

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.

Successful Cord Blood Stem Cell Transplantation for Primary Cutaneous CD8-positive Aggressive Epidermotropic Cytotoxic T-cell Lymphoma Complicated with Cerebral Infiltration

A 16-year-old boy, who had been initially examined for bilateral blepharedema and slight eruption, presented with rapidly deteriorating symptoms in associating with headache and consciousness disturbance. He was diagnosed to have primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma (PCAE-CTL) by a biopsy of the skin and brain. After whole-brain radiation and some courses of chemotherapy, cord blood transplantation was performed with myeloablative conditioning. After transplantation, the cerebral dysfunction gradually improved. Disease remission was confirmed by the disappearance of any abnormal findings on electroencephalogram and magnetic resonance imaging. PCAE-CTL is reported to be an extremely aggressive disease with a poor prognosis, but the timely performance of cord blood transplantation is considered to be a promising treatment strategy.

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.

Disease site as a determinant of survival outcome in patients with primary cutaneous peripheral T-cell lymphoma, unspecified: an analysis of 4057 cases from the US National Cancer Database

Primary cutaneous peripheral T-cell lymphoma, unspecified (PCPTL) accounts for <6% of cutaneous T-cell lymphoma cases. Due to its rarity, no large study exists in the literature on PCPTL. Among 4057 patients with PCPTL diagnosed from 2004 to 2014 in the National Cancer Database, 428, 913, 517, 754, and 1435 had lesions localized primarily to the upper extremity, head and neck, lower extremity, trunk, and overlapping lesion or unspecified site, respectively. PCPTL that primarily involved the head and neck had the longest overall survival (OS), followed by PCPTL that primarily involved the trunk, upper extremity, and lower extremity. Patients with lesions localized to the lower extremity had significantly shorter OS when compared to those with disease localized to other primary sites after adjusting for confounding factors. The difference in OS among disease sites was only significant in stage I disease, but not higher stages, and persisted in younger patients.

Transplantation in the Treatment of Primary Cutaneous Aggressive Epidermotropic Cytotoxic CD8-Positive T-Cell Lymphoma

BACKGROUND

Primary cutaneous aggressive epidermotropic cytotoxic CD8 positive T-cell lymphoma (CD8⁺ PCAETL) is a rare subtype of peripheral T-cell lymphoma with poor outcomes and without a standardized treatment strategy. Allogeneic hematopoietic stem cell transplantation (HSCT) has been suggested as a potential curative therapy.

PATIENTS AND METHODS

We conducted a retrospective case series. We identified 8 patients with the diagnosis of CD8⁺ PCAETL, 4 of whom also underwent allogeneic HSCT.

RESULTS

Eight patients were treated at our center with combination chemotherapy and several novel agents, including histone deacetylase inhibitors, brentuximab, and pralatrexate. Patients underwent a median of 8.5 treatments before HSCT. Six of the 8 patients examined, including all 4 who received an HSCT, were alive at their last follow-up.

CONCLUSION

Allogeneic HSCT is a promising treatment modality for CD8⁺ PCAETL. Because of the aggressive nature of this disease and lack of sustained remission with currently available therapies, HSCT should be considered early in the course of treatment. Two novel agents, brentuximab and pralatrexate, showed significant activity against CD8⁺ PCAETL, and may be incorporated earlier in the treatment course.

Managing Patients with Cutaneous B-Cell and T-Cell Lymphomas Other Than Mycosis Fungoides

Cutaneous lymphomas (CL) are a heterogeneous group of neoplasms characterized with clinical and histopathological variation, as well as overlap with benign dermatoses. Diagnosis and treatment of CLs is challenging and often requires a multidisciplinary approach. However, prognostic knowledge of these conditions and awareness of treatment options can help optimize appropriate use of available regimens, thereby improving care for patients. Here, we review the most recent literature and outline treatment themes for managing patients with cutaneous B-cell and T-cell lymphomas other than mycosis fungoides.

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 aggressive epidermotropic cytotoxic T-cell lymphomas: reappraisal of a provisional entity in the 2016 WHO classification of cutaneous lymphomas

Primary cutaneous CD8-positive aggressive epidermotropic T-cell lymphoma is a rare and poorly characterized variant of cutaneous lymphoma still considered a provisional entity in the latest 2016 World Health Organization Classification of Cutaneous lymphomas. We sought to better characterize and provide diagnostic and therapeutic guidance of this rare cutaneous lymphoma. Thirty-four patients with a median age of 77 years (range 19-89 years) presented primarily with extensive annular necrotic plaques or tumor lesions with frequent mucous membrane involvement. The 5-year survival was 32% with a median survival of 12 months. A subset of 17 patients had a prodrome of chronic patches prior to the development of aggressive ulcerative lesions. We identified cases with lack of CD8 or αβ T-cell receptor expression yet with similar clinical and pathological presentation. Allogeneic stem cell transplantation provided partial or complete remissions in 5/6 patients. We recommend the term primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma as this more broad designation better describes this clinical-pathologic presentation, which allows the inclusion of cases with CD8 negative and/or αβ/γδ T-cell receptor chain double-positive or double-negative expression. We have identified early skin signs of chronic patch/plaque lesions that are often misdiagnosed as eczema, psoriasis, or mycosis fungoides. Our experience confirms the poor prognosis of this entity and highlights the inefficacy of our standard therapies with the exception of allogeneic stem cell transplantation in selected cases.

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.

Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?

Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.

[Unusual course of CD8+ epidermotropic cutaneous T-cell lymphoma]

BACKGROUND

Aggressive epidermotropic cutaneous T-cell lymphoma (AECL) is a rare and aggressive form of lymphoma that exhibits systemic spread within a few months that is not preceded by any indolent form. Herein, we report a case of AECL occurring on foot lesions present for six years, and initially diagnosed as Woringer-Kolopp disease, or pagetoid cutaneous T-cell lymphoma.

PATIENTS AND METHODS

A male patient presented an ulcerated lesion of the ankle that had been present for six years. Biopsy revealed pagetoid migration of CD8+, CD2-, CD5-, CD7+, CD30- and CD56- lymphocytes with expression of cytotoxic markers and of Ki67 in over 60% of cells. The resulting diagnosis was one of pagetoid cutaneous T-cell lymphoma, also known as Woringer-Kolopp disease. Despite treatment with methotrexate and carmustine, the ulcer worsened rapidly within two months. Subsequent biopsy revealed epidermal and dermal infiltration with large cells of identical phenotype to that seen in the previous biopsy, with angiocentrism and expression of Ki67 in over 90% of cells, pointing to a diagnosis of AECL. Progression to disseminated ulceronecrotic lesions occurred rapidly, and the patient died of sepsis within a few months.

DISCUSSION

AECL is characterised by ulcerative-haemorrhagic lesions that develop aggressively without any preceding mild cutaneous lesions. Median survival is 12 months. Histological analysis shows pagetoid epidermotropism comprising large monomorphic CD8+, CD2- and CD5- cells with markers for cytotoxicity and high expression of Ki67. The initial indolent phase in the case we report herein accounts for the diagnostic confusion at the outset with Woringer-Kolopp disease. Negative status of CD2 and CD5 labels may allow prompt diagnosis of AECL.

CD68 expression is a discriminative feature of indolent cutaneous CD8-positive lymphoid proliferation and distinguishes this lymphoma subtype from other CD8-positive cutaneous lymphomas

BACKGROUND

Indolent cutaneous CD8+ lymphoid proliferation is a recently described rare entity among cutaneous T-cell lymphomas that typically presents with solitary skin lesions at acral sites. Separation from otherwise aggressive T-cell lymphomas bearing a cytotoxic CD8+ phenotype is fundamental to avoid unnecessary harmful treatment. However, up to now, no reliable discriminative marker has been identified.

OBJECTIVES

Motivated by these diagnostic quandaries, we have analyzed a large series of archived formalin-fixed paraffin-embedded (FFPE) specimens of atypical CD8+ cutaneous infiltrates with clear-cut diagnosis and clinical follow-up (n = 44) including five cases of indolent CD8+ lymphoid proliferation by using immunohistochemistry with the aim of obtaining markers predictive of subtype assignment.

RESULTS

We identified exclusive expression of CD68 by lymphoma cells within the subgroup of indolent CD8+ lymphoid proliferation (5/5 cases). Specific CD68 expression in this entity was confirmed by the application of several monoclonal antibodies (KP1, PG-M1, KiM1P) against the CD68 molecule available for FFPE tissue. In contrast, none of the infiltrates of the other CD8+ cutaneous lymphoma entities stained positive for CD68 (0/39).

CONCLUSIONS

Based on these observations, we suggest CD68 as a new discriminative marker which is helpful in distinguishing indolent CD8+ lymphoid proliferation from other CD8+ cutaneous lymphomas in ambiguous cases.