Cutaneous γδ T-cell lymphomas: a spectrum of presentations with overlap with other cytotoxic lymphomas. Am J Surg Pathol. 2012;36:1656-1665. [PMID: 23073324 DOI: 10.1097/pas.0b013e31826a5038]

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.

Atypical presentation of γ/δ mycosis fungoides with an unusual phenotype and SOCS1 mutation

Mycosis fungoides is the most frequent subtype of primary cutaneous T-cell lymphomas. The diagnosis is based on a thorough clinic-pathologic correlation, which can, especially in early-stage disease, be challenging due to similarities with several benign skin disorders such as psoriasis and atopic dermatitis. Here, we present a case of an 81-year-old man with a 20-year-long medical history of skin problems treated as psoriasis with limited effect. Since December 2021, the patient experienced worsening of his skin symptoms with rapidly growing tumors and widespread patches and plaques. Positron emission tomography/computed tomography evaluation revealed markedly metabolic activity related to the skin tumors and increased FDG uptake in several retroperitoneal lymph nodes. Histological assessment of skin biopsies demonstrated a highly proliferative T-cell lymphoma with a γ/δ+ and CD8+ cytotoxic phenotype. The morphology of the tumor cells appeared blastic with an abnormal immunephenotype CD3+, CD2-, CD5dim, CD4-, CD8+, CD56-, and CD30-. Next-generation sequencing detected a likely pathogenic SOCS1 mutation with an allele frequency of 72% as well as a STAT3 variant of unknown significance. This case highlights the diagnostic complexity of an indolent skin lymphoma evolving into an aggressive cytotoxic lymphoma.

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.

A Case of CD4 + T-Cell Lymphoma With Gamma-Delta Phenotype, Incidentally Manifesting in a Wound Debridement Sample

ABSTRACT

We report an 85-year-old male patient with a medical history significant for psoriasis who presented with a thigh wound that expanded slowly over the course of 9 months. The patient was previously treated with amputation of hand digits for osteomyelitis. Histologic examination of the tissue sample revealed a broad ulceration with large areas of necrosis extending into the subcutis. The edge of the specimen also revealed a nodular lymphoid infiltrate in the subcutaneous adipose tissue composed of atypical cells. These cells were only positive for CD3, CD4, and T-cell receptor (TCR) delta stains . The Ki-67 proliferation index of tumor cells was about 70%. The tumor cells were negative for CD30, CD8, CD56, TCR BF1, granzyme, TIA1, CD123, and Epstein-Barr encoding region (EBER)-ish stains. A diagnosis of gamma-delta T-cell lymphoma was made. Further imaging showed regional lymphadenopathy. The patient was started on mini-CHOP and filgrastim; however, the patient died within 1 month after the diagnosis. This is an interesting case of gamma-delta T-cell lymphoma that was incidentally diagnosed on a chronic wound. In addition, it showed a CD4 + , CD8 - phenotype that is exceedingly rare for T-cell lymphomas with gamma-delta phenotype.

Update on primary cutaneous T-cell lymphomas rare subtypes

Rare subtypes of cutaneous T-cell lymphomas (CTCL) include four entities, primary cutaneous γδ T-cell lymphoma, primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders, primary cutaneous acral CD8+ T-cell lymphoma, which were previously considered provisional and are now included in the new 5th World Health Organization classification of hematolymphoid tumors as distinct entities. An updated summary of the clinical, histological, and genomic characteristics of these uncommon CTCL subtypes is given in this review, with a focus on the growing body of knowledge regarding their classification and possible treatment strategies.

Pediatric cutaneous T-cell neoplasm and mimics with gamma-delta expression: Not always aggressive

Pediatric cutaneous T-cell lymphoma with γδ immunophenotype is extremely rare. Only a few cases of γδ T-cell neoplasm have been reported in the literature, and therefore little is known whether γδ T-cell neoplasms in children are distinct from their adult counterparts with respect to the clinicopathological presentation, behavior, and prognosis. In this study, we demonstrate three unique pediatric cutaneous T-cell neoplasm and mimics with increased γδ T cells. All cases showed an indolent clinical course.

Primary Cutaneous Gamma/Delta T-cell Lymphoma Simulating Lupus Erythematosus Panniculitis: What do we know about this aggressive mimicker?

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Diffusive mediator feedbacks control the health-to-disease transition of skin inflammation

The spatiotemporal dynamics of inflammation provide vital insights into the understanding of skin inflammation. Skin inflammation primarily depends on the regulatory feedback between pro- and anti-inflammatory mediators. Healthy skin exhibits fading erythema. In contrast, diseased skin exhibits expanding erythema with diverse patterns, which are clinically classified into five types: circular, annular, arcuate, gyrate, and polycyclic. Inflammatory diseases with expanding erythema are speculated to result from the overproduction of pro-inflammatory mediators. However, the mechanism by which feedback selectively drives the transition from a healthy fading erythema to each of the five types of diseased expanding erythema remains unclear. This study theoretically elucidates the imbalanced production between pro- and anti-inflammatory mediators and prospective treatment strategies for each expanding pattern. Our literature survey showed that eleven diseases exhibit some of the five expanding erythema, thereby suggesting a common spatiotemporal regulation underlying different patterns and diseases. Accordingly, a reaction-diffusion model incorporating mediator feedback reproduced the five observed types of diseased expanding and healthy fading patterns. Importantly, the fading pattern transitioned to the arcuate, gyrate, and polycyclic patterns when the productions of anti-inflammatory and pro-inflammatory mediators were lower and higher, respectively than in the healthy condition. Further depletion of anti-inflammatory mediators caused a circular pattern, whereas further overproduction of pro-inflammatory mediators caused an annular pattern. Mechanistically, the bistability due to stabilization of the diseased state exhibits circular and annular patterns, whereas the excitability exhibits the gyrate, polycyclic, arcuate, and fading patterns as the threshold of pro-inflammatory mediator concentration relative to the healthy state increases. These dynamic regulations of diffusive mediator feedback provide effective treatment strategies for mediator production wherein skins recover from each expanding pattern toward a fading pattern. Thus, these strategies can estimate disease severity and risk based on erythema patterns, paving the way for developing noninvasive and personalized treatments for inflammatory skin diseases.

Descriptive Analysis and Factors Influencing Survival in Patients With Primary Cutaneous Gamma-Delta T Cell Lymphoma. A Retrospective National Cancer Database Study

BACKGROUND

Gamma delta T cells gives rise to a rare malignancy called Primary cutaneous Gamma-Delta T cell lymphoma (PCGDTCL).

METHODS

From the National Cancer Database (NCDB), 110 (0.015%) patients with PCGDTCL were identified.

RESULTS

Males aged >60 years were the commonest cohort. Caucasian race was the most common (Caucasian: 79.09%, African American:16.36%). Most patients were diagnosed at stage 1 (52.33%), followed by stage 4 (30.23%). On analyzing income categories, <$48,000 group had 48.15% stage 4 (13/27) and 40.74% (11/27) stage 1. Overall survival (OS) of the study group at 3 years by Kaplan-Meier (KM) analysis was 46.6%. African American race (37.5%), income of <$48,000 (27.6%) and government insurance (38.8%) had lower survival rates in KM analysis. In the adjusted hazard ratio (HR) analysis, only age <=40 years compared to >60 years (0.165 [0.036, 0.768], P= .0217) reached significance. Although the group that did not receive any chemotherapy or radiation seemed to have a better survival by KM analysis at 74.3% at 3 years, significance was not seen in the adjusted HR estimates and majority of the patients in this group were stage 1. This group may have received topical treatments which may have not been captured in NCDB. Adjusted analysis also revealed chemoradiation to have a lower mortality risk compared to chemotherapy alone (0.229 [0.079, 0.670], P = .0071), suggesting that aggressive strategies may be required for management when needed.

CONCLUSION

Socioeconomic disparities significantly impact access to healthcare and are of particular importance in rare lymphomas.

SOHO State of the Art Updates and Next Questions | Challenging Cases in Rare T-Cell Lymphomas

Mature T- and NK-cell neoplasms (MTNKN) collectively represent a rare disorder, representing less than 15% of all non-Hodgkin lymphoma (NHL) cases and qualifying for orphan disease designation by the U.S. Food and Drug Administration (FDA). These consist of 9 families in the fifth revised WHO classification of lymphoid neoplasms, which are made up of over 30 disease subtypes, underscoring the heterogeneity of clinical features, molecular biology, and genetics across this disease group. Moreover, the 5 most common subtypes (peripheral T-cell lymphoma, not otherwise specified; nodal TFH cell lymphoma, angioimmunoblastic type; extranodal NK-cell/T-cell lymphoma; adult T-cell leukemia/lymphoma; and ALK-positive or -negative anaplastic large cell lymphoma) comprise over 75% of MTNKN cases, so other subtypes are exceedingly rare in the context of all NHL diagnoses and consequently often lack consensus on best practices in diagnosis and management. In this review, we discuss the following entities-enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), hepatosplenic T-cell lymphoma (HSTCL), subcutaneous panniculitis-like T-cell lymphoma (SPTCL), and primary cutaneous ɣδ T-cell lymphoma (PCGD-TCL) - with an emphasis on clinical and diagnostic features and options for management.

Aggressive Cutaneous Lymphomas and Their Mimics

Cutaneous lymphomas encompass a heterogeneous group of neoplasms with a wide spectrum of clinical presentations, histopathologic features, and prognosis. Because there are overlapping pathologic features among indolent and aggressive forms and with systemic lymphomas that involve the skin, clinicopathologic correlation is essential. Herein, the clinical and histopathologic features of aggressive cutaneous B- and T-cell lymphomas are reviewed. Indolent cutaneous lymphomas/lymphoproliferative disorders, systemic lymphomas, and reactive processes that may mimic these entities are also discussed. This article highlights distinctive clinical and histopathologic features, increases awareness of rare entities, and presents new and evolving developments in the field.

Primary Cutaneous Gamma-Delta T-cell Lymphoma: A Case Report and Review of Literature

Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) is a rare type of lymphoma, representing less than 1% of all cutaneous T-cell lymphomas. It is typically aggressive and chemotherapy-refractory. Hence, most institutions tend to employ intensive chemotherapy followed by stem cell transplantation although there is no standard of care established. We report a case of PCGD-TCL and discuss the challenges associated with the diagnosis and management of PCGD-TCL.

Recent advances in cutaneous lymphoma-implications for current and future classifications

The Revised European-American Classification of mature lymphoid neoplasms published in 1994 and the 2001, 2008 and 2016 WHO classifications that followed, were the product of international collaboration and consensus amongst haematopathologists, geneticists, molecular scientists and clinicians. Primary cutaneous lymphomas were fully incorporated into this process following the publication of the WHO-EORTC classification of cutaneous lymphomas in 2005. The definition, diagnostic criteria and recommended studies for primary cutaneous lymphoma continue to be refined. The 2022 International Consensus Classification represents the most recent update and an overview of all the main entities presenting primarily in the skin, together with the major changes in classification, are summarized herein. Primary cutaneous marginal zone lymphoma is segregated from other extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma) and downgraded to a lymphoproliferative disorder in line with its markedly indolent behaviour. In addition, two subtypes are recognised, based largely but not exclusively on whether they are heavy chain class-switched or IgM positive. Similarly, in keeping with a trend to greater conservatism, primary cutaneous acral CD8 positive T cell lymphoma is now also classified as a lymphoproliferative disorder. In addition, significant new insights into the biology of primary cutaneous lymphoma have also recently been forthcoming and will be presented. These studies have enhanced our knowledge of genetic, epigenetic and transcriptional changes in this group of diseases. They not only identify potential targets for novel therapies, but also raise as yet unanswered questions as to how we categorise cutaneous lymphomas, particularly with respect to relationships with similar lymphomas at extracutaneous sites.

Subcutaneous panniculitis-like T-cell lymphoma: an unusual cause of right thigh hypertrophy

A man in his mid-20s presented with a painless swelling over his right thigh, which had been progressively increasing over 3 years. He underwent an excisional biopsy for the same, which showed reactive lymphadenopathy. Since the last year and a half, he developed a lower abdominal wall swelling with mild redness over it. In addition, over the last few months before presentation to haematology outpatient clinic, he experienced bouts of fever, night sweats, anorexia, weight loss and right inguinal lymphadenopathy. On examination, splenomegaly was identified. In view of the patients' symptoms, he underwent a positron emission tomography scan, which showed hypermetabolic activity in the subcutaneous tissue sparing the lymph nodes and spleen. A deep skin punch biopsy taken from his right thigh was consistent with the diagnosis of subcutaneous panniculitis-like T-cell lymphoma αβ T-cell phenotype. The patient was treated successfully with oral steroids and on routine follow-up, he is in remission for 5 years.

Clinical, Diagnostic and Prognostic Characteristics of Primary Cutaneous Gamma Delta T-cell Lymphomas

Primary cutaneous γδ T-cell lymphoma (PCGDTL) is a rare subtype of non-Hodgkin lymphoma (NHL) that arises from T-cells with γδ T-cell receptors. The exact incidence of PCGDTL is unknown, as it is usually lumped with other cutaneous lymphomas, which are also uncommon. It is one of the peripheral T-cell lymphoma (PTCL) subtypes which is known to have a dismal prognosis due to poor response and the paucity of available therapies. Despite the rarity and uncertainties of PCGDTL, a number of studies over the past decade were published about the pathologic, diagnostic, cytogenetic and clinical features of this disease. These diagnostic advances will open the doors to explore new therapeutics for this rare entity, specifically targeted and immune therapies. In this review, we highlight these advances, summarize the contemporary treatment approaches, and shed the light on future potential therapeutic targets.

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.

The Diverse Roles of γδ T Cells in Cancer: From Rapid Immunity to Aggressive Lymphoma

γδ T cells are unique players in shaping immune responses, lying at the intersection between innate and adaptive immunity. Unlike conventional αβ T cells, γδ T cells largely populate non-lymphoid peripheral tissues, demonstrating tissue specificity, and they respond to ligands in an MHC-independent manner. γδ T cells display rapid activation and effector functions, with a capacity for cytotoxic anti-tumour responses and production of inflammatory cytokines such as IFN-γ or IL-17. Their rapid cytotoxic nature makes them attractive cells for use in anti-cancer immunotherapies. However, upon transformation, γδ T cells can give rise to highly aggressive lymphomas. These rare malignancies often display poor patient survival, and no curative therapies exist. In this review, we discuss the diverse roles of γδ T cells in immune surveillance and response, with a particular focus on cancer immunity. We summarise the intriguing dichotomy between pro- and anti-tumour functions of γδ T cells in solid and haematological cancers, highlighting the key subsets involved. Finally, we discuss potential drivers of γδ T-cell transformation, summarising the main γδ T-cell lymphoma/leukaemia entities, their clinical features, recent advances in mapping their molecular and genomic landscapes, current treatment strategies and potential future targeting options.

Gamma-Delta and CD20 Mycosis Fungoides: Two Cases Uncovered by Broad-Spectrum Immunostaining

ABSTRACT

Mycosis fungoides (MF) expresses T-cell markers and the alpha-beta T-cell receptor (TCR) complex. Here, we describe a case of MF with dual expression of TCR delta and TCR beta and a case of MF expressing the B-cell marker CD20. Both anomalies were detected after we instituted a broad-spectrum immunostaining panel for cutaneous T-cell lymphomas. These findings suggest anomalous immunophenotypes may be more common in MF than previously appreciated. Histopathologists should be aware of unexpected malleability in the immunophenotype of MF to avoid confusion with other subtypes of cutaneous lymphoma. Further research into the prevalence and significance of CD20 and TCR-delta expression in MF is encouraged.

Primary cutaneous gamma/delta T-cell lymphoma in Taiwan: A series of six cases with frequent solitary presentation and relatively indolent behavior

BACKGROUND

Primary cutaneous gamma/delta T-cell lymphoma (PCDG-TCL) is aggressive, frequently presenting as multiple plaques, tumors, and/or subcutaneous nodules.

METHODS

In this study, we conducted a retrospective study in a tertiary center in Taiwan to characterize this rare tumor.

RESULTS

We identified six patients. Five presented with a solitary lesion, including two with clinical impression of epidermal inclusion cyst or lipoma. Two of four evaluable cases exhibited epidermotropism, with one mimicking Pautrier microabscess. The neoplastic cells were pleomorphic and mostly medium- to large-sized. In all cases, the neoplastic cells expressed T-cell receptor (TCR)-γ and/or TCR-δ, with four co-expressing βF1. Two of these βF1+ cases co-expressed TCR-γ but not TCR-δ (two different clones). All were negative for Epstein-Barr virus (EBV), low stage, and treated with radiotherapy alone or combined chemotherapy and radiotherapy. In two patients, lymphoma relapsed in 3 and 7 months, respectively, and one patient died of the disease in 7 months. Four other patients were free of disease for 6 to 126 months.

CONCLUSION

PCGD-TCL cases in Taiwan are more commonly solitary, frequently with indolent courses. The two currently available TCR-δ clones alone might be insufficient to detect all tumors.

Gamma Delta T-Cell Receptor Lymphoma Causing Bilateral Pulmonary Embolism

Pulmonary embolism is a previously uncharacterized complication of primary cutaneous gamma delta T-cell lymphoma (PCGDTL), a type of cutaneous T-cell receptor lymphoma that accounts for less than 1% of non-Hodgkin’s lymphomas. We report the first documented case of bilateral pulmonary embolism in the setting of PCGDTL in a 30-year-old woman who presented with acute dyspnea.

Diagnosis and prognostic stratification of cutaneous lymphoma

Primary cutaneous lymphomas are a heterogenous group of non-Hodgkin's lymphoma of both T/natural killer-cell and B-cell origin and defined to primarily present in the skin without extracutaneous involvement at diagnosis. In contrast to nodal non-Hodgkin's lymphoma, cutaneous T-cell lymphomas (CTCL) are more generally seen than cutaneous B-cell lymphomas (CBCL). CTCL and CBCL have various subtypes and each subtype has specifically characteristic clinical, pathological, and prognostic features. The diagnostic methods and staging evaluation of cutaneous lymphomas is mostly common in various guidelines created by professional societies. The diagnosis is made comprehensively based on clinical, pathological, laboratory, radiological, and genetic findings. On the other hand, definite prognostic stratification has not been completely established yet in most cutaneous lymphomas. This article focuses on the general and novel diagnostic methods and the current findings about prognostic factors and stratification in cutaneous lymphomas.

Diagnosis and Management of Cutaneous Lymphomas Including Cutaneous T-cell Lymphoma

The cutaneous lymphomas are malignancies of T-cell and B-cell lymphocytes in which the skin is the primary organ of involvement. The cutaneous T-cell lymphomas include variants that can mimic the presentation of common skin diseases or arthropod bites. Mycosis fungoides, the most common cutaneous T-cell lymphoma, usually presents as fixed asymptomatic patches or plaques in sun-protected areas. The cutaneous B-cell lymphomas have fewer variants that often present as papules or nodules that can mimic nonmelanoma skin cancers. Some therapies for cutaneous lymphoma have unique side effects such as central hypothyroidism, hyperlipidemia, and peripheral neuropathy.

A Previously Unrecognized Granulomatous Variant of Gamma-Delta T-Cell Lymphoma

Primary cutaneous γδ T-cell lymphoma (PCGD-TCL) is an extremely rare and aggressive T-cell neoplasm with complex heterogeneity. We present a series of two patients who presented with firm, subcutaneous nodules and were diagnosed with PCGD-TCL. In both cases, biopsies demonstrated a both superficial and deep adnexotropic infiltrate comprised of angiocentric, medium- to large-sized atypical lymphocytes. The infiltrate extended into the panniculus. Immuno–histochemical stains highlighted atypical lymphocytes that expressed CD3, CD8 and CD56 but were negative for EBV ISH. A brisk histiocytic response with focal aggregation into granulomas was highlighted with a PG-M1 stain. The atypical lymphocytes were positive for gene rearrangements on a TCR delta stain and negative for βF-1. CT and PET scan in one of the two patients demonstrated diffuse, subcutaneous, ground-glass foci; hypermetabolic soft tissue nodules; and lymphadenopathy in the lungs, as well as splenomegaly. A diagnosis of histiocyte-rich PCGD-TCL was rendered. A histiocyte-rich, granulomatous variant of γδ T-cell lymphoma is extremely rare. Its potentially misleading resemblance to inflammatory granulomatous conditions could pose a diagnostic pitfall in this already challenging condition. This variant may resemble granulomatous mycosis fungoides and granulomatous slack skin syndrome, but it has a distinct, aggressive clinical outcome.

Gamma/delta T-cell lymphoma with mycosis fungoides-like clinical course transforming to "T-cell-receptor-silent" aggressive lymphoma: Description of one case

Primary cutaneous γδ T-cell lymphomas (PCGDTLs) are a heterogeneous group of lymphomas representing about 1% of primary cutaneous T-cell lymphomas (CTCLs) and mostly regarded as clinically aggressive. Current WHO-EORTC classification recognizes different clinic-pathologic subsets of PCGDTL, but it suggests that cases showing a mycosis fungoides (MF)-like clinical presentation and histopathology should be classified as MF irrespective of phenotype for their indolent course. Herein, we describe a case of γδ-MF, featuring at onset a granulomatous pattern, with subsequent clinical worsening signaled by the development of an ulcero-necrotic lesion and systemic dissemination, leading to death in 5 months. Clinical progression was sustained by a shift to mature T-cell lymphoma composed of medium to large-sized blastoid T-cells featuring a T-cell receptor (TCR) silent immunophenotype.

Gamma/Delta Phenotype in Primary Cutaneous T-cell Lymphomas and Lymphoid Proliferations: Challenges for Diagnosis and Classification

Primary cutaneous T-cell lymphomas pose a diagnostic challenge for dermatopathologists, hematopathologists, and general surgical pathologists. Recognition of gamma/delta phenotype in cutaneous T proliferations has been enhanced by the availability of antibodies against TCRgamma and delta for immunohistochemistry. Thus, reporting gamma/delta phenotype in a cutaneous T-cell lymphoid proliferation may indicate a significant change in therapy and a challenge for dermatologists and oncologists who treat these patients. Herein, we discuss primary cutaneous gamma/delta T-cell lymphoma, its differential diagnosis, and other skin lymphoid proliferations that may show gamma/delta phenotype. Awareness of the occurrence of gamma/delta phenotype in both T-cell lymphomas and benign lymphoid proliferations involving skin is crucial for a better interpretation of histopathologic findings. Integration of clinical presentation, morphology, immunoprofile, and molecular findings is key for a correct diagnosis and appropriate therapy of lesions displaying gamma/delta T-cell phenotype.

Successful salvage therapy for refractory primary cutaneous gamma-delta T-cell lymphoma with a combination of brentuximab vedotin and gemcitabine

Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) is a very rare lymphoma with an aggressive clinical course and a dismal outcome. The prognosis is linked to a pronounced resistance to chemotherapy and radiotherapy. No standard treatment approach is defined due to the low frequency of the disease and lack of prospective studies. CD30 is expressed in almost half of the cases of PCGD-TCL, which offers a potential therapeutic option. We report the successful treatment of a 68-year-old man who suffered PCGD-TCL with a combination of Brentuximab Vedotin and Gemcitabine after the failure of two lines of previous chemotherapy. CD30 expression was only partial. The treatment was very well tolerated and allowed the patient to benefit from allogeneic hematopoietic stem cell transplantation.

Secondary Gamma-Delta T-Cell Lymphoma Not Otherwise Specified (NOS) From Chronic Immunosuppression

Herein, we present the case of a 63-year-old female with a history of Behçet’s disease managed with long-term prednisone and azathioprine who initially presented for symptomatic anemia, which progressed to pancytopenia with neutropenic fever. Initial workup ruled out infectious etiologies but was indeterminate for immune-mediated or neoplastic causes. Bone marrow biopsy demonstrated a CD8+ gamma-delta T-cell neoplasm; however, imaging and skin biopsy pathology did not support hepatosplenic or cutaneous lymphoma involvement. By the 2017 World Health Organization (WHO) classifications, these findings were defined as gamma-delta peripheral T-cell lymphoma, not otherwise specified (NOS). This is suspected to be secondary to chronic immunosuppression from long-term steroid and azathioprine use. The patient was treated with one cycle of the EPOCH chemotherapy regimen ((etoposide, vincristine, cyclophosphamide, doxorubicin, and prednisone), but the treatment course was complicated by an angioinvasive fungal infection and the patient subsequently transitioned to symptom-focused therapy in a hospice facility.

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.

Monomorphic Epitheliotropic Intestinal T-Cell Lymphoma With Secondary Cutaneous Involvement: A Diagnostic Challenge

ABSTRACT

A 45-year-old woman presented with a solitary breast nodule that histologically corresponded to a dense dermal/subcutaneous infiltration of atypical cytotoxic T-lymphocytes (CD3+, CD8+, CD56+, TIA-1+, CD5-, CD4-, CD30-, EBV-), resembling subcutaneous panniculitic T-cell lymphoma. The presence of TCRδ gene rearrangement and the absence of βF1 expression let to suspect the diagnosis of primary cutaneous γδT-cell lymphoma. As a consequence of jejunum perforation following chemotherapy treatment, a mucosal atypical lymphoid infiltration with marked epitheliotropism was observed in the resected intestinal sample, and the diagnosis of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) was finally established. Disease progression appeared with multiple erythematous plaques showing a dense lichenoid atypical cytotoxic T-cell infiltrate with intense epidermotropism, mimicking primary cutaneous epidermotropic aggressive CD8+ T-cell lymphoma. MEITL is an uncommon and aggressive peripheral T-cell lymphoma that often presents in adults with gastrointestinal symptoms. Secondary cutaneous involvement is a rare phenomenon that may show clinicopathologic and immunohistochemical features that overlap with different subtypes of primary cutaneous cytotoxic T-cell lymphomas. In the absence of gastrointestinal symptoms, the diagnosis may be challenging, and only the evidence of underlying MEITL may allow to establish the definite diagnosis.

An Enteropathy-like Indolent NK-Cell Proliferation Presenting in the Female Genital Tract

Natural killer (NK) cell enteropathy is a lymphoproliferative disorder, initially described by Mansoor and colleagues, that presents in the gastrointestinal tract, and is often mistaken for extranodal NK/T-cell lymphoma on first assessment. This population of cells in this process have an NK-cell phenotype (CD3, CD56, CD2, CD7), lacks evidence of Epstein-Barr virus infection, has germline rearrangement of the T-cell receptor, and a very indolent clinical course. Indeed, many of such patients had been originally diagnosed as having an NK/T-cell lymphoma, and subsequently received chemotherapy. We report a unique case where an indolent lymphoproliferative disorder with features that resemble NK-cell enteropathy is encountered for the first time outside the gastrointestinal tract, specifically in the female genitourinary tract. We provide morphologic, immunophenotypic, and molecular documentation of such, in association with a completely indolent clinical behavior of this type of process.

Cellular origins and genetic landscape of cutaneous gamma delta T cell lymphomas

Primary cutaneous γδ T cell lymphomas (PCGDTLs) represent a heterogeneous group of uncommon but aggressive cancers. Herein, we perform genome-wide DNA, RNA, and T cell receptor (TCR) sequencing on 29 cutaneous γδ lymphomas. We find that PCGDTLs are not uniformly derived from Vδ2 cells. Instead, the cell-of-origin depends on the tissue compartment from which the lymphomas are derived. Lymphomas arising from the outer layer of skin are derived from Vδ1 cells, the predominant γδ cell in the epidermis and dermis. In contrast, panniculitic lymphomas arise from Vδ2 cells, the predominant γδ T cell in the fat. We also show that TCR chain usage is non-random, suggesting common antigens for Vδ1 and Vδ2 lymphomas respectively. In addition, Vδ1 and Vδ2 PCGDTLs harbor similar genomic landscapes with potentially targetable oncogenic mutations in the JAK/STAT, MAPK, MYC, and chromatin modification pathways. Collectively, these findings suggest a paradigm for classifying, staging, and treating these diseases.

A Systematic Approach to the Cutaneous Lymphoid Infiltrates: A Clinical, Morphologic, and Immunophenotypic Evaluation

CONTEXT.—

The evaluation of cutaneous lymphoid infiltrates, both neoplastic and inflammatory, occurs very frequently in routine dermatopathologic examination and consultation practices. The "tough" cutaneous lymphoid infiltrate is feared by many pathologists; skin biopsies are relatively small, whereas diagnostic possibilities are relatively broad. It is true that cutaneous lymphomas can be difficult to diagnose and that in many circumstances multiple biopsies are required to establish a correct diagnostic interpretation. As a reminder, one should understand that low-grade cutaneous lymphomas are indolent disorders that usually linger for decades and that therapy does not result in disease cure. It is also important to remember that in most circumstances, those patients will die from another process that is completely unrelated to a diagnosis of skin lymphoma (even in the absence of specific therapy).

OBJECTIVE.—

To use a clinicopathologic, immunophenotypic, and molecular approach in the evaluation of common lymphocytic infiltrates.

DATA SOURCES.—

An in-depth analysis of updated literature in the field of cutaneous lymphomas was done, with particular emphasis on updated terminology from the most recent World Health Organization classification of skin and hematologic tumors.

CONCLUSIONS.—

A diagnosis of cutaneous lymphoid infiltrates can be adequately approached using a systematic scheme following the proposed ABCDE system. Overall, cutaneous T- and B-cell lymphomas are rare and "reactive" infiltrates are more common. Evaluation of lymphoid proliferations should start with a good sense of knowledge of the clinical presentation of the lesions, the clinical differential considerations, and a conscientious and appropriate use of immunohistochemistry and molecular tools.

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.

A Case of Fever and Erythema Nodosum-Like Lesions Leading to a New Diagnosis of Gamma-Delta T-Cell Lymphoma Complicated by Hemophagocytic Lymphohistiocytosis

A 69-year-old Vietnamese female presented with fever and new-onset tender subcutaneous nodules on her trunk and lower extremities initially thought to be clinically consistent with erythema nodosum. A biopsy showed an atypical, predominantly lobular lymphocytic panniculitis with admixed neutrophils, karyorrhectic debris, and histiocytes with subcutaneous fat necrosis. Immunohistochemistry was consistent with gamma-delta T-cell lymphoma. The patient was initiated on a chemotherapy regimen of cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone (CHOEP) with partial remission, and is currently undergoing evaluation for bone marrow transplant. This case highlights the ability of cutaneous gamma-delta T-cell lymphoma to mimic more common cutaneous conditions such as erythema nodosum, and stresses the importance of a broad differential for new presentation of tender subcutaneous nodules with concomitant systemic symptoms.

Primary cutaneous γδ T-cell lymphoma with unusual immunophenotype: A case report and review of published work

Primary cutaneous γδ T-cell lymphoma (CGD-TCL) is a rare form of primary cutaneous lymphoma. The histopathological features of CGD-TCL are still unclear because of its rarity. Here, we report a case of a 77-year-old Japanese man who presented with a 9-month history of erythematous plaques on his left forearm. Skin biopsy specimens revealed the infiltration of atypical medium/large-sized lymphocytes from the epidermis to the deep dermis. Atypical lymphocytes were positive for CD3, CD5, CD8 and Vδ1, and negative for CD4, CD7, CD56, EBER-ISH, intracellular antigen-1, granzyme B and perforin. CD30 was partially expressed. We also reviewed 246 cases of CGD-TCL from the published work. CD4^- CD8^- double-negative cases were 113 of 196 cases (57.6%), followed by CD4^- CD8⁺ cases (52/196, 26.5%). CD5 was expressed in 25.8% of the cases (34/132). At least one cytotoxic molecule marker was expressed in 150 of 160 cases (93.8%). Some cases showed an indolent clinical course, especially in mycosis fungoides-like CGD-TCL cases. CD5 positivity and lack of cytotoxic molecule expression could be associated with a better prognosis. In addition, CD30 expression was found in approximately half of CGD-TCL cases (51/112 cases), suggesting that brentuximab vedotin could be a good treatment option for such patients. Further studies with more cases with detailed clinical and pathological information are necessary to elucidate the etiology and prognostic markers of this entity.

Peripheral T-Cell Lymphoma Arising in Patients With Chronic Lymphocytic Leukemia

OBJECTIVES

To describe three further cases of anaplastic large cell lymphoma (ALCL) occurring in patients with preexisting chronic lymphocytic leukemia (CLL). We also reviewed the literature of previously published cases.

METHODS

We discuss the clinical features, histopathology, and outcomes for three patients with ALCL and CLL from Perth, Australia. The cases were also included in a literature review of existing cases and comparisons were made with our cohort.

RESULTS

The three patients included two men (aged 77 and 74 years) and one woman (aged 66 years). All had a history of untreated CLL with diagnosis established 4 to 16 years before. They had lymphadenopathy and/or cutaneous/soft tissue lesions that proved to be ALCL, ALK+ (one case) or ALCL, ALK- (two cases).

CONCLUSIONS

Further research is required in this area to establish prognostic and management recommendations. Increasing numbers of cases are being described. Positron emission tomography with computed tomography was not useful in our cohort for diagnosing progression.

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.