T-Cell Receptor-γ in Gamma-Delta Phenotype Cutaneous T-Cell Lymphoma Can Be Accompanied by Atypical Expression of CD30, CD4, or TCRβF1 and an Indolent Clinical Course

Primary Cutaneous Anaplastic Large Cell Lymphoma With TCR-γδ Expression: A Case Series of Eleven Patients of a Rare Immunophenotypic Variant

BACKGROUND

Primary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis (LyP) are indolent CD30-positive lymphoproliferative disorders that rarely express TCR-γδ. However, primary cutaneous gamma-delta T-cell lymphoma (pcGDTCL), characterized by TCR-γδ expression on neoplastic cells, is a rare, aggressive cutaneous T-cell lymphoma with a poor prognosis. Accurate differentiation is essential due to distinct clinical behavior and treatment.

METHODS

We identified 11 TCR-γδ-positive pcALCL cases from internal and consultation files, verified by two cutaneous lymphoma experts, with clinicopathologic data recorded.

RESULTS

The median age was 68 years (range 38-95). Most cases presented as a single dermal lesion on the upper extremities. All were ALK-negative, CD30-positive (> 90% tumor cells), TCR-βF1-negative, and diffusely TCR-γδ-positive. CD4-/CD8- (54.5%) and CD4+/CD8- (45.5%) immunophenotypes were observed. CD2 (63.6%) and CD3 (54.5%) were the most common T-cell antigens. Ulceration, inflammation (both 45.5%), and necrosis (36.4%) were frequent. Angiotropism, angiocentricity, and myxoid stroma appeared in one case; epidermotropism in two. Four of ten tested were DUSP22-rearranged, and TP63 was negative in all eight tested.

CONCLUSIONS

Most ALK-negative TCR-γδ-positive pcALCL were CD4-/CD8-, followed by CD4+/CD8-. DUSP22 rearrangement occurred in 40% of cases, similar to reports in typical pcALCL. Its prognosis and the role of DUSP22 are yet to be clarified.

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

ABSTRACT

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

Primary Cutaneous Gamma-Delta T Cell Lymphomas: A Case Series and Overview of the Literature

Primary cutaneous gamma-delta T cell lymphomas (PCGDTCLs) are rare and aggressive cutaneous malignancies that have been diagnostically challenging for dermopathologists and clinicians since their first published descriptions in 1991. Since then, the availability of immunostaining for T cell receptors γ and δ in formalin-fixed paraffin-embedded samples has greatly increased our knowledge of the gamma-delta phenotype by showing that it may also be present in the context of indolent entities, such as mycosis fungoides (MFs) and lymphomatoid papulosis, and this has raised questions concerning its diagnostic and prognostic implications. We here describe the histological and clinical differences between the dermo-epidermal and subcutaneous sub-groups of PCGDTCL observed in a cohort of 20 patients attending a single experienced centre, with particular focus on cases with an MF-like presentation, which are still less well defined than those of classic MF.

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.

Silent T-cell receptor cutaneous T-cell lymphoma associated to a clonal plasma cell proliferation

Within T-cell lymphomas (TCL) there are 2 entities expressing gamma-delta TCR: hepatosplenic gamma-delta T-cell lymphoma (HSGDTL) and the primary cutaneous gamma-delta T-cell lymphoma (PCGDTL). PCGDTL is a rare form of Tcell lymphoma with specific tropism for skin that have a dismal prognosis. Although even rarer, there have been reports of TCL with loss of expression of the TCR, which have been termed peripheral TCL TCR-silent type. We report the case of a cutaneous TCR-silent type lymphoma associated to a clonal plasma cell proliferation with an ominous outcome that led to a lot of discussion in its classification. Due to the aggressiveness of the disease and the scant evidence about therapy in this strange entity the outcome was fatal. We report a unique case of a TCR-silent cutaneous TCL with an exceptional histopathology, prolonged clinical evolution and a subsequent plasma cell clonal expansion.

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.

T-cell receptor-δ expression and γδ+ T-cell infiltrates in primary cutaneous γδ T-cell lymphoma and other cutaneous T-cell lymphoproliferative disorders

AIMS

The diagnosis of cutaneous γδ T-cell lymphoma (GDTCL) requires the identification of γδ chains of the T-cell receptor (TCR). Our aim in this study was, by using a new monoclonal antibody (mAb) against TCRδ, to evaluate TCRδ expression in formalin-fixed paraffin-embedded (FFPE) skin tissue from TCRγ+ cutaneous T-cell lymphoma (CTCL), and to assess TCRδ expression within a spectrum of other cutaneous lymphoproliferative disorders (CLPDs).

METHODS AND RESULTS

Twelve cases (10 patients) with TCRγ+ CTCL and 132 additional CLPD cases (127 patients) were examined, including mycosis fungoides (MF) (n = 60), cutaneous GDTCL (n = 15), subcutaneous panniculitis-like T-cell lymphoma (SPTCL) (n = 11), and CD30⁺ lymphoproliferative disorder (LPD) (n = 24). Clone H-41 against TCRδ was used on a Leica Bond-3 automated stainer to label FFPE slides. H-41 immunostaining was graded as percentage infiltrate: high (50-100%), moderate (10-49%), and low (0-9%). In TCRγ+ tumours, 12 of 12 (100%) patients showed TCRδ expression comparable to TCRγ expression. No (0%) TCRγ+ cases were negative for TCRδ. In all CLPDs, TCRδ expression was as follows: GDTCL, 16 of 20 cases (14 of 15 patients) high, two moderate, and two low; MF, 0 of 60 cases high, nine moderate, and 51 low; CD30⁺ LPD, one of 24 cases high, two moderate, and 21 low; and SPTCL, 0 of 11 cases (0 of 9 patients) high, two moderate, and two low. Three MF-like cases and one SPTCL-like case showed high expression; the remainder showed low expression.

CONCLUSIONS

mAb H-41 against TCRδ matches TCRγ in immunostaining FFPE tissues from GDTCL, supporting H-41 as a replacement for mAb γ3.20. TCRδ expression in our study suggests that the true occurrence of γδ+ non-GDTCL CTCL/CLPD may be lower than suggested by the recent literature.

Immunophenotypic Shifts in Primary Cutaneous γδ T-Cell Lymphoma Suggest Antigenic Modulation: A Study of Sequential Biopsy Specimens

Primary cutaneous γδ T-cell lymphoma (PCGD TCL), an aggressive type of lymphoma, accounts for approximately 1% of all primary cutaneous lymphomas. We have occasionally observed changes in T-cell antigen expression (immunophenotypic [IP] shift) over time, a phenomenon that is considered rare in T-cell lymphoma including cutaneous T-cell lymphoma. Therefore, we assessed sequential biopsies of PCGD TCL for possible IP shifts of the lymphoma cells. We searched for cases of PCGD TCL with consecutive biopsies to perform a comprehensive immunohistochemical analysis of paired specimens. A median of 12 markers per case was tested. We evaluated the percentage of neoplastic lymphocytes and determined the differential expression of antigens (gain, loss, increase or decrease). We identified 9 patients with PCGD TCL with consecutive biopsies. All (100%) cases had IP shifts of at least 1 antigen, whereas overall 22 pairs of markers were shifted: gain of reactivity occurred in 7 (31.8%) and loss in 3 (13.6%); increased reactivity in 4 (18.2%) and decreased in 8 (36.4%). Molecular analysis of TCRγ showed identically sized monoclonal rearrangements between biopsy pairs in 4/4 (100%) patients. There was no correlation between IP shifts and the clinical appearance of lesions, histopathologic or cytologic features, or molecular rearrangements. IP shifts are common in PCGD TCL, occurring in all patients in this study and involving a variety of antigens. IP shifts do not seem to be linked to changes in the T-cell clone and are without obvious clinical or morphologic correlates. The occurrence of IP shifts in PCGD TCL suggests that antigen modulation may be involved in pathogenesis. IP shifts are somewhat frequent in T-cell lymphoma; however, it does not suggest a second neoplasm, and molecular studies can be used to determine clonal identity.

Primary Cutaneous T-Cell Lymphomas Showing Gamma-Delta (γδ) Phenotype and Predominantly Epidermotropic Pattern are Clinicopathologically Distinct From Classic Primary Cutaneous γδ T-Cell Lymphomas

Primary cutaneous gamma-delta (γδ) T-cell lymphoma is a rare disease that typically involves the dermis and subcutis. Cases of primary cutaneous T-cell lymphomas showing γδ phenotype and predominantly epidermotropic pattern (EγδTCL) are not well defined. In this series, cases of primary cutaneous T-cell lymphomas showing γδ phenotype were reviewed and classified as predominantly epidermotropic (EγδTCL) when >75% of lymphoma cells resided in the epidermis or predominantly dermal and/or subcutaneous (DSγδTCL). Clinical, pathologic, and immunophenotypic features were compared in 27 biopsies from 13 patients of EγδTCL and 13 biopsies from 7 patients of DSγδTCL. The lymphoma cells were diffusely positive for CD3 and T-cell receptor (TCR)γ, mostly positive for granzyme B and TIA-1, variably positive for CD8, CD7, and CD30, and negative for CD4 and TCRβ. Two patients with EγδTCL had dissemination to lymph nodes and 1 to the lung; 1 patient with DSγδTCL had gastrointestinal involvement. The median survival of patients with EγδTCL was not reached, and with a median follow-up of 19.2 months, 3/13 died. In contrast, the median survival of patients with DSγδTCL was 10 months, and after a median follow-up of 15.6 months, 5/5 died (P<0.01). EγδTCL is a rare presentation of cutaneous T-cell lymphoma that can be distinguished from DSγδTCL based on the extent of epidermotropism and has a better prognosis and longer median survival than DSγδTCL. However, although EγδTCL resembles mycosis fungoides clinically and histologically, a subset of EγδTCL is more likely to behave more aggressively than typical mycosis fungoides.

Pagetoid reticulosis tumor cells with double expression of TCRγδ and TCRαβ: an off-target phenomenon or genuine expression?

Pagetoid reticulosis (PR) is a low-grade primary cutaneous T-cell lymphoma showing localized patches or plaques with an intrapeidermal proliferation of neoplastic T-cells with heterogeneous immunophenotype. We describe a 73-year-old woman with a 8-year history of gluteal lesions of PR, whom large blast cells were CD4/CD8 double negative T-cells with an activated cytotoxic profile. The case was investigated using a broad panel of monoclonal antibodies including TCRγM1, a new available antibody that recognizes the γ chain subunit of the T-cell receptor (TCR) in formalin-fixed paraffin-embedded tissue. Large blast cells were simultaneously positive for TCRαβ and TCRγδ with an activated cytotoxic phenotype. It is worldwide accepted the mutual exclusive expression of TCRαβ and TCRγδ but six different studies, dealing with TCRγδ expression in various types of extra-nodal lymphomas, reported cases whom tumor cells expressed simultaneously TCRαβ and TCRγδ. Our data and those of similar reports, suggest the possibility of existence of a subset of extra-nodal T-cell lymphomas showing simultaneous expression by tumor cells of TCRγδ and TCRαβ with an immunoprofile consistent with an origin from TCRγδ+ T lymphocytes. This unusual subset has preferential, but not exclusive, skin localization and variable epidermotropism.