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]

Peripheral T-cell and NK cell lymphoproliferative disorders: cell of origin, clinical and pathological implications

T-cell lymphoproliferative disorders are a heterogeneous group of neoplasms with distinct clinical-biological properties. The normal cellular counterpart of these processes has been postulated based on functional and immunophenotypic analyses. However, T lymphocytes have been proven to be remarkably capable of modulating their properties, adapting their function in relationship with multiple stimuli and to the microenvironment. This impressive plasticity is determined by the equilibrium among a pool of transcription factors and by DNA chromatin regulators. It is now proven that the acquisition of specific genomic defects leads to the enforcement/activation of distinct pathways, which ultimately alter the preferential activation of defined regulators, forcing the neoplastic cells to acquire features and phenotypes distant from their original fate. Thus, dissecting the landscape of the genetic defects and their functional consequences in T-cell neoplasms is critical not only to pinpoint the origin of these tumors but also to define innovative mechanisms to re-adjust an unbalanced state to which the tumor cells have become addicted and make them vulnerable to therapies and targetable by the immune system. In our review, we briefly describe the pathological and clinical aspects of the T-cell lymphoma subtypes as well as NK-cell lymphomas and then focus on the current understanding of their pathogenesis and the implications on diagnosis and treatment.

Primary Cutaneous T-cell Lymphoma With Coexpression of T-Cell Receptors αβ and γδ

T lymphocytes belong to 2 distinct sublineages that express either αβ or γδ T-cell receptor (TCR) complex. Although malignancy is a great instigator of lineage infidelity, as exemplified by aberrant expression of numerous lineage markers in lymphoma cells, malignant T cells rarely coexpress αβ and γδ TCR complexes. Similarly, only rare cases of CD4/CD8 double-positive primary cutaneous T-cell lymphoma have been reported. In this report, we describe a remarkable case of primary cutaneous T-cell lymphoma coexpressing αβ and γδ TCR complexes, strong diffuse CD8, and a very restricted coexpression of CD4 and CD8. A 66-year-old man was referred to our center for treatment of a persistent eczematoid eruption of 6 years of duration. An initial biopsy demonstrated not only marked spongiosis, but also an epidermotropic population of CD4 small mature T cells with partial expression of CD8. The process remained indolent for another year, followed by an abrupt progression with development of plaques and tumors. Repeat biopsies of these lesions demonstrated a superimposed population of large anaplastic T cells extensively involving the dermis and epidermis. The large cells showed a strong uniform expression of CD3, CD8, CD45RA, CD5, granzyme, TIA1, perforin, TCR-β, and TCR-γ and a weaker but unambiguous expression of CD4, CD25, CD2, and CD56. TCR gene rearrangement studies showed clonal rearrangements for TCR-β and TCR-γ with identical peaks to those seen in the biopsy from a year earlier. The patient developed lymphadenopathy, with a biopsy showing nodal involvement by a morphologically and phenotypically identical neoplastic T-cell population. The disease showed partial response to systemic chemotherapy with development of new plaques, but these new lesions have regressed with radiation therapy.

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.

Paediatric cutaneous lymphomas: a review and comparison with adult counterparts

Primary cutaneous lymphomas (CL) in children is rare. Only a few studies focused specifically on paediatric CL and therefore little is known whether primary CL in children are similar to or different from their adult counterparts with respect to the clinicopathological presentation, behaviour and prognosis. An extensive literature search using PubMed/MEDLINE from January 1995 through July 2014 was undertaken for articles reporting cases of paediatric CL. In addition, we identified 31 children with CL in our institutions. Mycosis fungoides and lymphomatoid papulosis are the two most prevalent lymphoma forms in children. A few entities of cutaneous lymphomas such as cutaneous diffuse large B-cell lymphoma leg type, and Sézary syndrome have not been reported so far in children. Other lymphoma entities such as hydroa vacciniforme-like lymphoma are mostly seen in certain geographic areas (Asia, Central and South America). In the paediatric population, low-malignant indolent forms such as primary cutaneous marginal zone lymphoma and primary cutaneous follicle centre lymphoma are very rare, whereas the more aggressive forms of B-cell lymphomas, precursor lymphoblastic lymphomas, and blastic plasmacytoid dendritic cell neoplasm are the most common forms in children, mostly involving the skin secondarily. Most paediatric lymphomas have similar clinicopathological features and course as their adults counterparts, particularly in the group of cutaneous T-cell lymphomas. The spectrum of cutaneous B-cell lymphomas in children significantly differs from the one in adults. Diagnostic work-up and treatment of paediatric patients with lymphomas are best achieved in close collaboration with paediatric haematopathologists and oncologists.

Aggressive epidermotropic cutaneous CD8+ lymphoma: a cutaneous lymphoma with distinct clinical and pathological features. Report of an EORTC Cutaneous Lymphoma Task Force Workshop

AIMS

Aggressive epidermotropic cutaneous CD8(+) lymphoma is currently afforded provisional status in the WHO classification of lymphomas. An EORTC Workshop was convened to describe in detail the features of this putative neoplasm and evaluate its nosological status with respect to other cutaneous CD8(+) lymphomas.

METHODS AND RESULTS

Sixty-one CD8(+) cases were analysed at the workshop; clinical details, often with photographs, histological sections, immunohistochemical results, treatment and patient outcome were discussed and recorded. Eighteen cases had distinct features and conformed to the diagnosis of aggressive epidermotropic cutaneous CD8(+) lymphoma. The patients typically present with widespread plaques and tumours, often ulcerated and haemorrhagic, and histologically have striking pagetoid epidermotrophism. A CD8(+) /CD45RA(+) /CD45RO(-) /CD2(-) /CD5(-) /CD56(-) phenotype, with one or more cytotoxic markers, was found in seven of 18 patients, with a very similar phenotype in the remainder. The tumours seldom involve lymph nodes, but mucosal and central nervous system involvement are not uncommon. The prognosis is poor, with a median survival of 12 months. Examples of CD8(+) mycosis fungoides, lymphomatoid papulosis and Woringer-Kolopp disease presented the typical features well documented in the CD4(+) forms of those diseases.

CONCLUSIONS

Aggressive epidermotropic cutaneous CD8(+) lymphoma is a distinct lymphoma that warrants inclusion as a distinct entity in future revisions of lymphoma classifications.

Pseudocarcinomatous hyperplasia mimicking squamous cell carcinoma in a case of CD56-positive cytotoxic T-cell lymphoma

We present the case of an 84-year-old patient with a cutaneous CD56 positive cytotoxic T-cell lymphoma associated with substantial pseudocarcinomatous hyperplasia mimicking squamous cell carcinoma (SCC). The patient presented with a 7-month history of several progressive, ulcerated plaques on his right forearm. An initial biopsy showed changes consistent with a diagnosis of SCC for which the patient underwent surgical treatment. Several months later, the patient developed recurrent ulcerated plaques on the right forearm of which several biopsies were performed. The biopsies repeatedly showed marked pseudocarcinomatous hyperplasia resembling SCC. Deeper punch biopsies, however, showed a dense superficial and deep infiltrate of markedly atypical lymphocytes. Immunohistochemical analysis revealed strong positive staining for CD3, CD8, CD56 with negative stains for CD30 and Epstein-Barr virus-encoded small non-polyadenylated RNAs (EBER). Staining for beta F1 and gamma-delta T-cell receptor (γδ TCR) were both negative. This constellation was most consistent with a diagnosis of cutaneous peripheral T-cell lymphoma, unspecified in association with marked pseudocarcinomatous hyperplasia. Our case adds cutaneous peripheral T-cell lymphoma, unspecified to the list of conditions associated with pseudocarcinomatous hyperplasia (PCH) and illustrates once again the potential pitfalls of distinguishing marked pseudocarcinomatous hyperplasia from SCC.

A fatal case of primary cutaneous gamma-delta T-cell lymphoma complicated by HLH and cardiac amyloidosis

Gamma–delta T-cell lymphomas (GD-TCL) are rare and rapidly fatal neoplasms that are often associated with Hemophagocytic Lymphohistiocytosis (HLH), a syndrome of fevers, cytopenias, and multiorgan failure that often leads to a rapid death. We report the first case demonstrating an association between GD-TCL, HLH, and cardiac amyloidosis, presenting a novel mechanism for rapid deterioration in these patients.

Cytotoxic T-cell and NK-cell lymphomas: current questions and controversies

The cytotoxic T-cell and natural killer (NK)-cell lymphomas and related disorders are important but relatively rare lymphoid neoplasms that frequently are a challenge for practicing pathologists. This selective review, based on a meeting of the International Lymphoma Study Group, briefly reviews T-cell and NK-cell development and addresses questions related to the importance of precise cell lineage (αβ-type T cell, γδ T cell, or NK cell), the implications of Epstein-Barr virus infection, the significance of anatomic location including nodal disease, and the question of further categorization of enteropathy-associated T-cell lymphomas. Finally, developments subsequent to the 2008 World Health Organization Classification, including the recognition of indolent NK-cell and T-cell disorders of the gastrointestinal tract are presented.

Gamma-delta t-cell lymphomas

Gamma-delta T-cell lymphomas are aggressive and rare diseases originating from gamma-delta lymphocytes. These cells, which naturally play a role in the innate, non-specific immune response, develop from thymic precursor in the bone marrow, lack the major histocompatibility complex restrictions and can be divided into two subpopulations: Vdelta1, mostly represented in the intestine, and Vdelta2, prevalently located in the skin, tonsils and lymph nodes. Chronic immunosuppression such as in solid organ transplanted subjects and prolonged antigenic exposure are probably the strongest risk factors for the triggering of lymphomagenesis. Two entities are recognised by the 2008 WHO Classification: hepatosplenic gamma-delta T-cell lymphoma (HSGDTL) and primary cutaneous gamma-delta T-cell lymphoma (PCGDTL). The former is more common among young males, presenting with B symptoms, splenomegaly and thrombocytopenia, usually with the absence of nodal involvement. Natural behaviour of HSGDTL is characterised by low response rates, poor treatment tolerability, common early progression of disease and disappointing survival figures. PCGDTL accounts for <1% of all primary cutaneous lymphomas, occurring in adults with relevant comorbidities. Cutaneous lesions may vary, but its clinical behaviour is usually aggressive and long-term survival is anecdotal. Available literature on gamma-delta T-cell lymphomas is fractioned, mostly consisting of case reports or small cumulative series. Therefore, clinical suspicion and diagnosis are usually delayed, and therapeutic management remains to be established. This review critically analyses available evidence on diagnosis, staging and behaviour of gamma-delta T-cell lymphomas, provides recommendations for therapeutic management in routine practice and discusses relevant unmet clinical needs for future studies.

Primary Cutaneous Gamma-Delta T-Cell Lymphoproliferative Disorder in a 3-Year-Old Boy

Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) is a rare disorder, constituting less than 1% of primary cutaneous lymphomas. Most cases occur in adults and may present as plaques or nodules with ulceration. Here we describe an unusual case of PCGD-TCL in a 3-year-old boy who presented with asymptomatic subcutaneous nodules. To our knowledge, this report represents one of the youngest reported patients with gamma-delta lymphoma/lymphoproliferative disorder. In addition, our patient has an indolent clinical presentation with greater than 1 year clinical follow-up. Because gamma-delta T-cell lymphomas are exceedingly rare in children, we acknowledge that the clinical course/outcome in young patients is still unclear. We hope to add to the recognition that PCGD-TCLs demonstrate a wide clinical spectrum of disease with relatively indolent presentations in some cases.

Peripheral T-cell lymphomas with cytotoxic phenotype in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is relatively common, and patients occasionally develop other neoplasms; however, patients who develop other types of lymphomas are rare. We encountered 3 patients with CLL/SLL (one 59-y-old man and 2 women aged 56 and 66 y) who developed T-cell lymphomas. Both women developed ALK anaplastic large cell lymphomas (ALCLs), whereas the man developed CD8 peripheral T-cell lymphoma, not otherwise specified. All 3 T-cell lymphomas expressed granzyme B and perforin, indicating a cytotoxic immunophenotype. In 1 case, the first presentation was a lymph nodal composite lymphoma. In the other 2 cases, the T-cell lymphomas arose <1 year after the diagnosis of CLL/SLL and were identified in a lymph node in one case and in the spleen in the other. The patient with a composite lymphoma (SLL/ALK ALCL) was treated and was free of disease at last follow-up, whereas the other 2 patients succumbed to their disease, 1 month and 7 months after the diagnosis of T-cell lymphoma. Peripheral T-cell lymphomas rarely occur in CLL/SLL patients. On the basis of our small series, those with a cytotoxic phenotype appear to be more common in this setting. The occurrence of ALK ALCL in 2 older patients was especially surprising and suggested that CLL/SLL may have played a role in the development of ALCL.