Cytotoxic/natural killer cell cutaneous lymphomas. Report of EORTC Cutaneous Lymphoma Task Force Workshop

Primary Cutaneous Small/Medium CD4+ T-Cell Lymphomas: A Heterogeneous Group of Tumors With Different Clinicopathologic Features and Outcome

Purpose

To define the clinical and pathologic characteristics of primary cutaneous small/medium CD4+ T-cell lymphoma (PCSM-TCL) and identify parameters of prognostic significance.

Patients and Methods

We have investigated 24 patients with primary cutaneous lymphomas composed of small/medium mature T-cells with a βF1, CD3, CD4+ and/or noncytotoxic, CD8– and CD30– phenotype. The proliferation index and CD8+ infiltrating cells were quantified with an automated image analysis system.

Results

Sixteen patients presenting with solitary or localized plaques or small nodules (< 3 cm) had an indolent course. Only three patients experienced repeated cutaneous relapses, and none of them died as a result of the disease after 1 to 168 months (median, 17 months) of follow-up. The tumors had a low proliferation (median Ki-67, 9% ± 5%) and an intense infiltrate of reactive CD8+ (median, 20% ± 11.7%). Five patients presenting with rapidly evolving large tumors or nodules (≥ 5 cm) had an aggressive disease and died with extracutaneous dissemination 18 to 36 months after diagnosis (median, 23 months). These tumors had a significantly higher proliferation (median Ki-67, 22% ± 11.3%; P < .05) and lower number of infiltrating CD8+ (median, 1% ± 3%; P < .05) than the previous group. A third group of three patients had a peculiar clinical presentation with multifocal relapsing lesions without extracutaneous dissemination after a long period of follow-up ranging from 41 to 92 months. Histologically, these cases had an intense infiltrate of eosinophils.

Conclusion

PCSM-TCL is a heterogeneous group of tumors with differentiated clinical and pathological characteristics with impact in the outcome of the patients.

Subcutaneous panniculitislike T-cell lymphoma with hemophagocytosis: complete remission with BFM-90 protocol

Subcutaneous panniculitislike T-cell lymphoma (SPTCL) is an uncommon type of cutaneous lymphoma. In many cases, SPTCL is accompanied by hemophagocytic syndrome (HPS), resulting in prominent systemic symptoms. The natural history, optimal treatment strategy, and prognostic factors associated with this malignancy are not well defined. We report an 11-year-old boy of SPTCL with HPS who was initially treated with conventional cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy, but progressed later on therapy. Subsequently, the child was treated with multiagent combination chemotherapy as per BFM-90 protocol and achieved complete remission, and has remained so for 3 years. This report suggests the value of this particular multiagent combination chemotherapy regimen in the treatment of patients with SPTCL and HPS.

Angiocentric lesions of the head and neck

Angiocentric lesions of the head and neck encompass a variety of benign and malignant lesions. Not unexpectedly the sequelae of an angiocentric process independent of its benign or malignant nature is one of tissue ischemia with a potential for either breakdown or reparative fibrosis. Therefore, the clinical presentations can be very similar despite a varied pathogenesis. Among the benign reactive infiltrates that will be considered are angiocentric eosinophilic fibrosis, Wegener's granulomatosis, microscopic polyangiitis and cocaine associated mid line facial destruction. We will discuss other conditions which enter into the differential diagnosis either clinically or histologically including Erdheim Chester disease and mid line facial undermining unrelated to an angiocentric event specifically in the context of trigeminal trophic ulcer and relapsing polychondritis. The two main neoplastic conditions exhibiting angiocentricity are in the context of lymphomatoid granulomatosis and NK/T cell lymphoma; hence these two particular hematologic dyscrasias will be discussed in some detail in this review.

NK-cell intravascular lymphomatosis--a mini-review

The majority of cases of intravascular lymphomatosis (IVL) is derived from B cells. However, IVL may also arise from T cells, or more rarely NK cells. The clinicopathological findings in six cases of NK-cell IVL (NK-IVL), including one new case, were summarised and compared with B-cell IVL (B-IVL) and T-cell IVL (T-IVL). Earlier onset of disease and female predominance were found in NK-IVL. NK-IVL was typically Epstein-Barr virus (EBV)-positive, whereas EBV was rarely detected in B-IVL. Cutaneous manifestations were common in NK-IVL with constant EBV infection. B-IVL showed a more favourable prognosis than T- or NK-IVL. Irrespective of immunophenotype, however, IVL showed a less favourable prognosis than ordinary lymphomas within the same immunophenotype. In summary, IVL of the B-, T- and NK-cell phenotypes is clinicopathologically distinct and shows similarities to their more common counterparts, i.e. diffuse large B-cell lymphoma, peripheral T-cell lymphoma, unspecified and extranodal NK/T-cell lymphoma, nasal type.

The ontogeny and fate of NK cells marked by permanent DNA rearrangements

A subset of NK cells bears incomplete V(D)J rearrangements, but neither the consequence to cell activities nor the precise developmental stages in which recombination occurs is known. These are important issues, as recombination errors cause cancers of the B and T lineages. Using transgenic recombination reporter mice to examine NK cell dynamics in vivo, we show that recombination(+) NK cells have distinct developmental patterns in the BM, including reduced homeostatic proliferation and diminished Stat5 phosphorylation. In the periphery, both recombination(+) and recombination(-) NK cells mediate robust functional responses including IFN-gamma production, cytolysis, and tumor homing, suggesting that NK cells with distinct developmental histories can be found together in the periphery. We also show that V(D)J rearrangement marks both human cytolytic (CD56(dim)) and immunoregulatory (CD56(bright)) populations, demonstrating the distribution of permanent DNA rearrangements across major NK cell subsets in man. Finally, direct quantification of rag transcripts throughout NK cell differentiation in both mouse and man establishes the specific developmental stages that are susceptible to V(D)J rearrangement. Together, these data demonstrate that multipotent progenitors rather than lineage-specified NK progenitors are targets of V(D)J recombination and that NK cells bearing the relics of earlier V(D)J rearrangements have different developmental dynamics but robust biological capabilities in vivo.

Intravascular cytotoxic T-cell lymphoma: A case report and review of the literature

Intravascular lymphoma (IVL) is a rare subtype of extranodal diffuse large B-cell lymphoma in the World Health Organization classification. Although the majority of cases are of B-cell lineage, cases of IVL with a T-cell phenotype and, rarely, histiocytic and natural killer (NK)-cell phenotypes have been reported. We report a case of T-cell IVL with a cytotoxic phenotype. A 62-year-old male presented with erythematous patches and plaques on the lower extremities, and a biopsy revealed IVL with an activated cytotoxic phenotype (CD56(+), perforin+, granzyme B+, TIA-1+, CD3epsilon(+), CD20(-), CD4(-), CD8(-), CD5(-), and T-cell receptor [TCR] betaF1(-)), consistent with either NK-cell or T-cell origin. TCR gene analysis showed a monoclonal T-cell population, supporting the diagnosis of a T-cell IVL. Although the patient's skin lesions were refractory to combination chemotherapy and salvage chemotherapy regimens, there has been no evidence of disease progression in 24 months of follow-up.

Indolent CD8-positive lymphoid proliferation of the ear: a distinct primary cutaneous T-cell lymphoma?

The authors report 4 cases of cutaneous lymphoproliferation unusual by their histology and their clinical presentation. Each presented with a history of a slow growing nodule on the ear. Despite the indolent clinical evolution, the histology suggested a high-grade lymphoma. All lesions consisted of a dense, diffuse proliferation of monomorphous medium-sized T cells throughout the dermis and subcutis. There was no epidermotropism and a grenz zone was clearly present in each case. The tumor cells displayed irregular blastlike nuclei, with small nucleoli and clear chromatin and had a CD3+, CD8+, CD4+, TIA1+, granzyme B(-)immunophenotype with a loss of other T-cell antigens. The 3 cases with available material for polymerase chain reaction studies displayed a monoclonal T-cell rearrangement of the T-cell receptor-gamma chain. These cases do not correspond to a recognized cutaneous T-cell lymphoma as described in the recent WHO/EORTC classification. The apparent striking propensity for the ear suggests that they might represent a specific entity. Further cases are needed to confirm this hypothesis. It is important for such indolent lesions to be known to avoid over treatment.

Subcutaneous panniculitis-like T-cell lymphoma: definition, classification, and prognostic factors: an EORTC Cutaneous Lymphoma Group Study of 83 cases

In the WHO classification, subcutaneous panniculitis-like T-cell lymphoma (SPTL) is defined as a distinct type of T-cell lymphoma with an aggressive clinical behavior. Recent studies suggest that distinction should be made between SPTL with an alpha/beta T-cell phenotype (SPTL-AB) and SPTL with a gammadelta T-cell phenotype (SPTL-GD), but studies are limited. To better define their clinicopathologic features, immunophenotype, treatment, and survival, 63 SPTL-ABs and 20 SPTL-GDs were studied at a workshop of the EORTC Cutaneous Lymphoma Group. SPTL-ABs were generally confined to the subcutis, had a CD4-, CD8+, CD56-, betaF1+ phenotype, were uncommonly associated with a hemophagocytic syndrome (HPS; 17%), and had a favorable prognosis (5-year overall survival [OS]: 82%). SPTL-AB patients without HPS had a significantly better survival than patients with HPS (5-year OS: 91% vs 46%; P<.001). SPTL-GDs often showed (epi)dermal involvement and/or ulceration, a CD4-, CD8-, CD56+/-, betaF1- T-cell phenotype, and poor prognosis (5-year OS: 11%), irrespective of the presence of HPS or type of treatment. These results indicate that SPTL-AB and SPTL-GD are distinct entities, and justify that the term SPTL should further be used only for SPTL-AB. SPTL-ABs without associated HPS have an excellent prognosis, and multiagent chemotherapy as first choice of treatment should be questioned.

Extranodal type T/NK-cell lymphoma with an atypical clinical presentation

Peripheral-type natural killer (NK)- or T-cell lymphomas are rare disorders characterized with clonal proliferation of mature lymphocytes. They have been linked to chronic and active Epstein-Barr virus infection (CAEBV), which itself is not defined as a malignant hematological disorder. The authors present a patient with T/NK-cell lymphoma involving skin, kidneys, spleen, pancreas, and meninges. She was remarkable for having the mosaic feature of more than one type of extranodal T/NK-cell lymphoma. She also had mixed findings of CAEBV that might have been attributed both to hypersensitivity to mosquito bites and to hemophagocytic lymphohistiocytosis.

Innate versus Adaptive Immunity: A Paradigm Past Its Prime?

Studies in tumor immunology have relied upon the classic paradigm of distinct innate and adaptive parts of the immune system. However, recent advances in immunology suggest that this division may be overly simplistic, with emerging evidence of a breakdown in conventional hallmarks of each system. Here, we provide an overview of this area and discuss how the concept of a continuum of immune cell populations suggests novel areas of investigation in cancer research.

Selected Diagnostic Problems in Neoplastic Dermatopathology

Context.—Selected cutaneous neoplasms share features with benign counterparts or have subtle morphologic features that could be overlooked by the pathologist.

Objective.—To present clues to the diagnosis of potentially deceptive malignancies, including desmoplastic malignant melanoma, nevoid malignant melanoma, subcutaneous lymphoma, metastatic breast carcinoma, and epithelioid sarcoma.

Data Sources.—Published literature and personal experience.

Conclusions.—Knowledge of commonly misdiagnosed cutaneous neoplasms will help the general surgical pathologist avoid these potential pitfalls in neoplastic dermatopathology.

A case of primary cutaneous nasal type NK/T-cell lymphoma and review of the literature

INTRODUCTION

Cutaneous T-cell lymphoma subtypes are now better identified thanks to progress in immunohistochemistry. This article describes a new case of primary cutaneous natural killer/T-cell lymphoma of nasal type (NKTL-NT) and reviews 18 other cases of this rare neoplasm.

CASE REPORT

A 79-year-old man presented with a 3-cm nodular tumor of the left leg occurring on a primary chronic lymphedema of the legs. The lesion was CD56+, CD3 intracytoplasmic+, CD45+ and Epstein-Barr virus+. A comprehensive workup including CT scan and bone marrow biopsy was negative and a diagnosis of NKTL-NT with a primary cutaneous involvement was made. The patient was free of disease under multi-agent chemotherapy after 24 months of follow-up.

DISCUSSION

After reviewing 18 other cases of primary cutaneous NKTL-NT, we conclude that the prognosis of these lymphomas is usually poor. However, limited cutaneous forms have a longer median survival than extracutaneous variants.

Lymphome T cutané épidermotrope cytotoxique CD8+ « agressif » : difficultés de prise en charge chez un malade atteint d’une dystrophie myotonique de Steinert

INTRODUCTION

Primary cutaneous "aggressive" CD8-positive epidermotropic cytotoxic T-cell lymphoma is a rare subset of cutaneous cytotoxic T/NK lymphomas that clearly differs from mycosis fungoides, whether CD4+ or CD8+, by the presence of rapidly evolving tumoral cutaneous lesions, foci of keratinocytes necrosis, a cytotoxic T phenotype and a poor prognosis.

CASE REPORT

A 33-year-old man with Steinert's myotonic dystrophy was referred for evaluation of rapidly worsening cutaneous tumors along with marked deterioration of general status. Clinical, histological and immunohistological data led to the diagnosis of primary cutaneous CD8+ epidermotropic cytotoxic T-cell lymphoma. CHOP chemotherapy was effective despite cardiac toxicity in the setting of Steinert's dystrophy, but the patient relapsed and died of pulmonary sepsis after chemotherapy was resumed.

DISCUSSION

The treatment of primary cutaneous epidermotropic CD8+ cytotoxic T-cell lymphoma is not codified. CHOP chemotherapy is usually the first-line therapy but relapses are frequent with median survival of no more than 34 months. In our patient, an additional difficulty was the cardiac toxicity of cytostatic drugs linked to the myopathy which prevented the use of high dosages, requiring a change of therapeutic regimen.

Intravascular lymphoma: a neoplasm of 'homeless' lymphocytes?

Intravascular lymphoma (IVL) is an extremely rare form of non-Hodgkin lymphoma characterized by almost exclusive growth of neoplastic lymphocytes within blood vessel lumen. IVL is morphologically characterized in most instances by large cells with B-cell lineage. IVL is an aggressive and usually disseminated disease that predominantly affects elderly patients, resulting in poor PS, B-symptoms, anemia, and high lactate dehydrogenase serum level. The brain and skin are the most commonly involved sites; nodal disease is rare. Survival after conventional chemotherapy is disappointing, with a relevant impact of diagnostic delay and lethal complications. Notwithstanding these results, IVL limited to the skin (cutaneous variant) is a favorable presentation with distinctive clinical characteristics. Moreover, differences in clinical presentation with Eastern Countries IVL cases, mostly associated with hemophagocytic syndrome, do exist. Intensive combinations containing drugs with higher central nervous system bioavailability are needed in cases with brain involvement; the role of high-dose chemotherapy with autologous stem cell transplantation should be investigated in younger patients with unfavorable features. The present review will discuss the most recent acquisitions related either to diagnosis and immunophenotypic/biologic characteristics as well as clinical/therapeutic issues of IVL.

Three cases of lymphomatoid papulosis with a CD56+ immunophenotype

We report 3 cases of lymphomatoid papulosis (LyP) with a CD56+, cytotoxic immunophenotype. All 3 patients presented with clinical histories typical of LyP, with one patient having associated mycosis fungoides. Histologically, two cases were type A LyP and one was type B. All 3 cases demonstrated a T-cell receptor clone in lesional skin without evidence of blood involvement. The atypical lymphocytes in each of the 3 cases expressed cytotoxic granules (T-cell intracellular antigen-1+ and granzyme B+) and were CD8+ and CD56+. Expression of CD56 is associated with a poor prognosis in subcutaneous panniculitis-like T-cell lymphoma and blastic natural killer cell lymphoma. However, the two cases of CD56+ LyP previously reported and the 3 cases in this series all appear to be pursuing an indolent course with no evidence of systemic disease.

Chemokine receptor expression in cutaneous T cell and NK/T-cell lymphomas: immunohistochemical staining and in vitro chemotactic assay

Interactions between chemokines and chemokine receptors are involved in migration and invasion of lymphoma cells. We investigated expression profiles of CXCR3 and CCR4 by immunohistochemistry and flow cytometry, and their biologic behaviors by real-time horizontal chemotaxis assay in cutaneous T cell and NK/T-cell lymphomas (TCLs). Tumor cells in mycosis fungoides (MF) constantly expressed CXCR3 at the patch stage, and expressed CCR4 at the tumor stage and in the folliculotropic variant of MF. Neoplastic cells at the plaque stage expressed CXCR3 and/or CCR4. Sezary cells in the dermis and circulation were positive for CCR4. Epidermotropic atypical cells in pagetoid reticulosis expressed CXCR3. CD30 cells exclusively expressed CCR4 in anaplastic large-cell lymphoma, and CXCR3 and/or CCR4 in lymphomatoid papulosis. In CD8TCL and extranodal NK/TCL characterized by extensive epidermotropism, tumor cells were positive for CXCR3. These data demonstrated preferential expression of CXCR3 in epidermotropic tumor cells, and of CCR4 in dermis-based lymphomas. In chemotaxis assays, CCR4 tumor cells in MF and CXCR3 tumor cells in CD8TCL migrated to thymus and activation-regulated chemokine and inducible protein-10, respectively. Therefore, spatial and temporal interactions between chemokine receptors and their ligands seem to dictate recruitment and retention of lymphoma cells in the skin.

Cutaneous Intravascular NK-cell Lymphoma: Report of a Rare Variant Associated With Epstein-Barr Virus

Intravascular lymphoma (IVL) is a rare variant of non-Hodgkin lymphoma with a predilection for skin and brain. Except a few cases of T-cell lineage, most of the reported cases were large B-cell lymphomas. We encountered a case of cutaneous IVL in a 71-year-old woman presenting with multiple erythematous patches and nodules on her trunk and extremities. The intravascular large cells showed an immunophenotype of CD3epsilon(+);, CD5(-), CD20(-), CD30(-), CD56(+), and TIA-1(+). The lymphoma cells were also positive for Epstein-Barr virus by Epstein-Barr virus-encoded RNA in situ hybridization test and the T-cell receptor gene was germline. This IVL differs from nasal type NK/T-cell lymphoma only by its intravascular nature. Only 3 cases of intravascular NK-cell lymphoma have been reported before. Because this variant is extremely rare, our case is documented and compared with the 3 previously reported cases.

Primary cutaneous aggressive epidermotropic CD8+cytotoxic T-cell lymphoma with atypical presentation

Primary cutaneous aggressive epidermotropic CD8(+) cytotoxic T-cell lymphoma is characterized by a proliferation of epidermotropic CD8(+) cytotoxic T cells and an aggressive clinical behavior. Patients present with localized or disseminated eruptive papules, nodules and tumors. We report a case of primary cutaneous aggressive epidermotropic CD8(+) cytotoxic T-cell lymphoma with unusual clinical manifestation. The lesion occurred as multiple brownish macules and flat-topped papules on the hands, feet and face in a 25-year-old woman.

CD4/CD8 double-negative epidermotropic cutaneous T-cell lymphoma: an immunohistochemical variant of mycosis fungoides

BACKGROUND

Mycosis fungoides (MF) is an epidermotropic cutaneous T-cell lymphoma in which the tumor cells express a mature T-helper memory phenotype, ie, CD3(+), CD4(+), CD8(-), CD45RO(+), with a T-cell receptor (TCR) of the alpha/beta heterodimer. A minority of patients have an unusual immunohistochemical profile consisting of a CD4(-), CD8(+) mature T-cell phenotype. An aberrant CD4/CD8 double-negative (DN) immunophenotype in patients with early MF has rarely been reported.

OBJECTIVES

We sought to evaluate the frequency of CD4/CD8 DN immunophenotype in patients with early MF, and to study their clinical, histopathologic, and immunohistochemical features, and the course of their disease.

METHODS

Our departmental archives were searched for patients with early-stage MF and CD4/CD8 DN immunophenotpye.

RESULTS

Of the 140 patients with early MF immunophenotyped in our laboratory, 18 (12%) showed CD4 and CD8 expression in less than 10% of their intraepidermal T cells on fresh-frozen and paraffin-embedded samples. The group included 13 male and 5 female patients; 14 adults and 4 children; and 15 Jews and 3 Arabs. In all, 8 had classic MF and 10 had unusual clinical variants (5 hypopigmented, 3 localized, 1 ichthyosiform, 1 purpuric). All received skin-targeted therapies and all had an indolent course (mean follow-up 3.5 years). Histopathology revealed early MF. Results of immunohistochemical analysis of the intraepidermal lymphocytes were as follows: CD3(+), CD4(-), CD8(-) in all patients; CD7(-) in all of 17; CD45RO(+) in 15 of 16; T-cell-restricted intracellular antigen-1(+) in 11 of 15; CD30(+) in 2 of 16; and CD56(+) in 2 of 16. A betaF1(+)/delta(-) phenotype, indicating a TCR of the alpha/beta heterodimer, was found in 8 of 16; betaF1(-)/delta(+) phenotype, indicating a TCR of the gamma/delta heterodimer, in 1 of 16; betaF1(-)/ delta(-) in 5 of 16; and no determinable phenotype in 2 of 16. The TCR gamma gene was clonally rearranged in 10 of 16 patients.

LIMITATION

This was a single-center case series.

CONCLUSIONS

There is a subgroup of patients with early MF that exhibit a CD4/CD8 DN immunophenotype. In our region, this aberrant immunophenotype is not as rare as reflected in the literature, is overrepresented in the unusual clinical variants of MF, and does not seem to have prognostic significance. Like CD4(+) MF, the tumor cells represent memory T cells and in many cases express alpha/beta TCR, but unlike CD4(+) MF, they have a mostly cytotoxic phenotype. We suggest that CD4/CD8 DN MF should be recognized as another immunohistochemical variant of this lymphoma.

The protean spectrum of non-Hodgkin lymphomas with prominent involvement of subcutaneous fat

BACKGROUND

Subcutaneous T-cell lymphoma (STCL) represents a controversial entity and a confused concept in the field of cutaneous T-cell lymphomas (CTCLs). Recently, alpha/beta+/CD8+ STCL has been recognized by the new World Health Organization (WHO)-European Organization for Research and Treatment of Cancer (EORTC) classification of primary cutaneous lymphomas as a distinct entity in the group of CTCLs.

OBSERVATIONS

We reviewed a series of 53 biopsies from 26 patients (F : M = 19:7; median age: 48; range 18-87) of cutaneous B- and T-cell lymphomas characterized by prominent involvement of the subcutaneous tissue. We could classify our cases according to the following seven categories--(i) STCL: n = 16; (ii) extranodal NK/T-cell lymphoma, nasal type: n = 2; (iii) cutaneous gamma/delta T-cell lymphoma: n = 2; (iv) anaplastic CD30+ large T-cell lymphoma: n = 1; (v) diffuse large B-cell lymphoma, secondary cutaneous: n = 3; (vi) lymphoplasmacytic lymphoma, secondary cutaneous: n = 1; (vii) specific cutaneous manifestations of myelogenous leukemia: n = 1.

CONCLUSIONS

We demonstrated the protean nature of lymphomas with prominent involvement of the subcutaneous fat tissues. The term STCL should be restricted to a homogeneous group of cases characterized morphologically by an exclusive involvement of subcutaneous tissues, immunohistochemically by a T-cytotoxic alpha/beta phenotype, and biologically by a relatively good prognosis.

Mycosis fungoides with a CD56+ immunophenotype

We report 3 cases of mycosis fungoides (MF) with a CD56+ cytotoxic immunophenotype. Each patient presented with a different clinical phenotype: one exhibited limited poikilodermatous patches (skin stage T1); one, widespread hypopigmented lesions (skin stage T2); and one, poikiloderma with a single cutaneous tumor (skin stage T3). MF was confirmed both histologically and by the presence of a T-cell receptor clone in lesional skin in all cases. CD56 and T-cell intracellular antigen-1 were expressed by the malignant lymphocytes in all patients and two expressed CD8. No sample demonstrated loss of the pan T-cell markers CD2 or CD3. None of the 3 developed systemic disease and T-cell receptor gene analysis of peripheral blood was polyclonal in all cases. Only 3 cases of CD56+ MF have been reported previously, none of which exhibited tumor-stage disease. Currently, the disease in our patients appears to be behaving in a manner similar to that predicted for MF with a normal immunophenotype but the prognosis has to be guarded in view of the rarity of this subtype.

NK/T-cell lymphomas ‘nasal type’: an Italian multicentric retrospective survey

OBJECTIVE

To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma 'nasal type' developed in Italian patients.

PATIENTS

Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma 'nasal type' were diagnosed in 10 Italian Hematology institutions.

RESULTS

All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20-80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding the stage of disease: 12 patients were in stage I; six in stage II; eight in stage IV. Diagnosis was based on the finding of a NK/T-cell phenotype at the histological and immunophenotypic examination of oropharyngeal or cutaneous lesions. All patients but one were treated with chemotherapy, alone in nine cases or associated to radiotherapy in 14 cases; two patients had chemotherapy, radiotherapy and surgery, while one patient underwent only surgery. Chemotherapy was anthracycline-based in 17 out of 25 cases. In those patients in whom radiotherapy was performed, radiation dosages ranged between 36 Gy and 47.5 Gy, with a median dosage of 40 Gy. Nine patients (34%) were responsive to the treatments: six patients obtained a complete remission and other three a partial remission. The remaining 17 patients resulted refractory or presented a limited response to therapy. The median disease-free survival was 14 months and the median overall survival time was 9 months.

CONCLUSION

The results of this retrospective survey confirmed that NK/T-cell lymphoma 'nasal type' is a very rare lymphoma in the Italian population, and it is characterized by a very bad prognosis. Due to the rarity of this disease, a standardized therapeutic approach is lacking. More data are needed to know the epidemiology of this kind of lymphoma in Europe.

Classification of cutaneous T-cell lymphoma: from Alibert to WHO-EORTC

Cutaneous T-cell lymphomas (CTCLs) represent a heterogeneous group of neoplasms originating from skin-homing T cells that show considerable variation in clinical presentation, histological appearance, immuno- phenotype, and prognosis. This review provides a historic overview of the classification of CTCLs from the first description of a patient with mycosis fungoides in 1806 to the recently published WHO-EORTC classification. Practical guidelines for the usage of the WHO-EORTC classification and relevant features of new or newly defined entities such as subcutaneous panniculitis-like T-cell lymphoma, extranodal NK/T-cell lymphoma, nasal type, primary cutaneous aggressive CD8-positive cytotoxic T-cell lymphoma, and cutaneous gamma/delta T-cell lymphoma are presented. The aim of this review is to contribute to a better communication between dermatologist and pathologist and in this way to a better diagnosis and classification of CTCLs.

Primary cutaneous follicular center cell lymphoma of the nose with maxillary sinus involvement in a pediatric patient

We report a primary cutaneous follicular center cell lymphoma (PCFCCL) that arose on the nose and the left naso-labial fold, spread to the left cheek, the left maxillary sinus, and the soft palate in a 16-year-old boy. Polychemotherapy was performed and the patient is disease-free after 41 months. This case is unusual because PCFCCL rarely arises on the nose, only occasionally disseminates to extracutaneous sites, and, to our knowledge, has never been described in pediatric patients.

Lymphome T cutané épidermotrope CD8+ cytotoxique d’évolution très agressive

BACKGROUND

Cutaneous CD8+ epidermotropic cytotoxic T-cell lymphoma is a recently described rare primary cutaneous lymphoma exhibiting aggressive clinical behavior. Only about twenty cases have been described in the literature. Below we report a case involving unusual association of cutaneous vasculitis and lymphoproliferation.

CASE REPORT

A 42-year-old senegalese man was hospitalized for cutaneous nodular lesions, which rapidly spread and became necrotic and ulcerated. he had recent weight loss with fever and multiple enlarged lymph nodes. Cutaneous histological analysis showed epidermotropic dermal infiltrate comprising medium and large cd8+ cytotoxic t-cells of unusual angiocentricity with cutaneous vasculitis and fibrinoid necrosis. the patient died 4 months after initiation of treatment with multi-agent chemotherapy.

DISCUSSION

This patient presented the characteristics of primary cutaneous CD8+ epidermotropic cytotoxic T-cell lymphoma described by Berti. The clinical findings in most cases consist of nodular and ulcerative cutaneous lesions. Histologically, the cutaneous infiltrate is composed of pleomorphic lymphocytes with marked and constant epidermotropism. Immunohistochemistry shows lymphocytes expressing a CD8+ phenotype and cytotoxic proteins, which probably accounts for the local and systemic aggressiveness of the disease, as well as the angiodestructive nature of the infiltrate and the necrotic lesions.

Regression of extranodal natural killer/T-cell lymphoma, nasal type with denileukin diftitox (Ontak® ) and bexarotene (Targretin® ): report of a case

Denileukin diftitox (Ontak) is a fusion protein comprising a diphtheria toxin and an interleukin (IL)-2 moiety that specifically targets CD25 (IL-2 receptor)-positive tumour cells. We report a patient with rapidly progressive Epstein-Barr virus-positive nasal type extranodal natural killer/T-cell lymphoma (extranodal NKTCL), treated with a combination of denileukin diftitox (Ontak) and oral bexarotene (Targretin). A significant regression of the cutaneous tumours was observed already after the first cycle of denileukin diftitox and was maintained for a period of 5 months with monthly cycles of denileukin diftitox. The treatment was well tolerated. Following this response the patient decided to stop the treatment. He was then followed by his oncologist and lost from dermatological follow-up. Shortly after treatment withdrawal the disease progressed and the patient received one cycle of doxorubicin (Caelyx). He died from septic shock syndrome 2 months later. To our knowledge this is the first case of extranodal NKTCL treated with denileukin diftitox and bexarotene. A striking, albeit transient, response occurred with this therapy. Combination treatment with denileukin diftitox and bexarotene should be further assessed in this aggressive type of cutaneous lymphoma.

Processos linfoproliferativos da pele: parte 2 - linfomas cutâneos de células T e de células NK

Os linfomas cutâneos de células T/NK constituem um grupo de doenças linfoproliferativas extranodais atualmente classificadas e subdivididas de acordo com o comportamento clínico segundo consenso da Organização Mundial de Saúde e da Organização Européia para Pesquisa e Tratamento do Câncer. Os linfomas cutâneos de células T/NK de comportamento clínico indolente compreendem a micose fungóide clássica, a micose fungóide foliculotrópica, a reticulose pagetóide, a cútis laxa granulomatosa, o linfoma cutâneo primário de grande célula anaplásica, a papulose linfomatóide, o linfoma subcutâneo de célula T paniculite-símile e o linfoma cutâneo primário de pequena e média célula T CD4+ pleomórfica. Os linfomas cutâneos de células T/NK de comportamento agressivo incluem a síndrome de Sézary, o linfoma extranodal de célula T/NK, tipo nasal, o linfoma cutâneo primário agressivo de célula T CD8+ epidermotrópica, o linfoma cutâneo de célula T <FONT FACE=Symbol>gd</FONT> e o linfoma cutâneo primário de célula T periférica, não especificado. O linfoma-leucemia de células T do adulto e a neoplasia hematodémica CD4+CD56+, embora considerados linfomas sistêmicos, são aqui abordados por apresentarem-se inicialmente na pele em significativo número de pacientes. O diagnóstico desses processos é realizado pelo exame histopatológico complementado pela análise do fenótipo das células neoplásicas, imprescindível no processo classificatório. O estadiamento para a avaliação da extensão anatômica da doença considera além do envolvimento cutâneo, o estado clínico e histológico dos linfonodos e das vísceras. Avaliação hematológica é fundamental na caracterização da síndrome de Sézary. Os tratamentos preconizados incluem terapêuticas dirigidas exclusivamente à pele, modificadores da resposta biológica e quimioterapia sistêmica.

Rimming of Adipocytes By Neoplastic Lymphocytes

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma of the skin presenting with histopathologic features simulating those of a lobular panniculitis. The presence of neoplastic T-lymphocytes forming a rim around the individual fat cells in the subcutaneous lobules, so-called "rimming" of adipocytes, is considered a characteristic morphologic feature of this type of cutaneous lymphoma. In this study we reviewed a series of 45 biopsy specimens of primary and secondary cutaneous B- and T-cell lymphomas and one of myeloid leukemia involving the subcutaneous tissues and showing rimming of adipocytes (subcutaneous panniculitis-like T-cell lymphoma: n = 16; mycosis fungoides, tumor stage: n = 3; aggressive epidermotropic CD8(+) T-cell lymphoma: n = 2; cutaneous gamma/delta T-cell lymphoma: n = 4; extranodal NK/T-cell lymphoma, nasal type: n = 4; cutaneous medium-large pleomorphic T-cell lymphoma, NOS: n = 5; CD4(+)/CD56(+) hematodermic neoplasm (blastic NK-cell lymphoma): n = 7; secondary cutaneous large B-cell lymphoma: n = 3; secondary cutaneous lymphoplasmacytic lymphoma: n = 1; specific cutaneous manifestations of acute myelogenous leukemia: n = 1). We could demonstrate that rimming of adipocytes by neoplastic cells can be recognized not only in subcutaneous panniculitis-like T-cell lymphoma, but also in several different entities of malignant lymphoma with skin involvement. Precise classification of cases with prominent involvement of the subcutaneous tissues can only be achieved upon precise correlation of clinicopathologic and phenotypic features. Rimming of adipocytes should not be considered specific of subcutaneous panniculitis-like T-cell lymphoma.

Clinicopathologic and Prognostic Significance of Cytotoxic Molecule Expression in Nodal Peripheral T-Cell Lymphoma, Unspecified

Cytotoxic molecules (CMs) are apoptosis-inducing molecules that are present in azurophilic cytoplasmic granules of T lymphocytes. Expression of TIA-1 and granzyme B was examined for 100 cases of nodal peripheral T-cell lymphoma, unspecified (PTCL-U) to assess clinicopathologic significance of CM. Forty-one were positive for at least one CM. Patients with CM-positive PTCL-U showed younger onset (median, 55 years vs. 64 years, P = 0.01) and less male predominance (male:female ratio, 21:20 vs. 44:15, P = 0.02). CM-positive PTCL-U was significantly associated with several clinical factors to indicate poor prognosis, in comparison with CM-negative PTCL-U, such as poorer performance status (P = 0.006), more frequent B-symptoms (68% vs. 35%, P = 0.002), higher serum lactate dehydrogenase levels (P = 0.003), and more frequent extranodal involvement, particularly bone marrow involvement (33% vs. 9%, P = 0.004). Epstein-Barr virus was mostly found in CM-positive PTCL-U (51% vs. 2%, P < 0.0001). The CM-positive group showed higher distribution of the International Prognostic Index (P = 0.009) and the Prognostic Index for T-cell lymphoma (P = 0.004) scores than CM-negative group. Complete remission rate was 30% for the former but 63% for the latter. Overall survival of CM-positive PTCL-U was significantly lower than that of CM-negative patients (P = 0.004). Multivariate analyses confirmed that CM expression is a significant prognostic factor, independent from other clinical factors or prognostic index scores. These findings suggest that nodal CM-positive PTCL-U show distinct clinicopathologic characteristics among the current category of PTCL-U.

Fatal subcutaneous panniculitis-like T-cell lymphoma with interface change and dermal mucin, a dead ringer for lupus erythematosus

We report a 48-year-old man who presented with ulcerated plaques and nodules of the lower extremities. Skin biopsies revealed a dense lymphocytic infiltrate involving the dermis and the subcutis in a lobular and septal pattern. No overt cytological atypia was present. Notably, several features resembling lupus erythematosus were present, including vacuolar interface change and abundant dermal mucin deposition. The patient developed pulmonary nodules, and a lung biopsy showed a perivascular and interstitial lymphoid infiltrate without overt atypia. The cutaneous and pulmonary lymphoid infiltrates showed similar immunohistochemical profiles: CD3(+) CD4(-) CD8(+/-) CD56(+). Monoclonal rearrangements of the T-cell receptor gamma gene with similar migration patterns were identified from both locations. The patient developed fatal hemophagocytic syndrome, involving liver, spleen, lymph nodes, and bone marrow. This case is one amongst the rare reports of subcutaneous panniculitis-like T-cell lymphoma with systemic involvement.

Natural killer cell neoplasms

Lymphoid neoplasms that are derived from natural killer (NK) cells are uncommon but distinct clinicopathologic disease entities. Three types have been recognized and categorized in the latest World Health Organization classification: extranodal NK cell lymphoma, nasal-type; aggressive NK cell leukemia; and blastic NK cell lymphoma. All NK tumor cells express the NK cell marker CD56, but they lack the expression of surface CD3 and the rearrangement of T-cell receptor genes, which distinguish them from T-lymphoid neoplasms. There is also a strong association with the Epstein-Barr virus, except in blastic NK cell lymphoma. Extranodal involvement by the NK cell tumor is common, especially in the nasal cavity, the skin, and the gastrointestinal tract. All 3 NK cell neoplasms are characterized by aggressive clinical course and poor response to treatment. Although the optimal treatment modality remains to be determined, good initial response to combined radiation therapy and chemotherapy has been observed in localized disease. Further studies in the basic biology of the NK cell and the pathology of NK cell neoplasms may shed light on the development of newer and more effective therapy.

Blastic natural killer cell lymphoma/leukemia (CD56-positive blastic tumor)

BACKGROUND

Blastic natural killer (NK) cell lymphoma/leukemia (BNKL) is an immature CD56-positive neoplasm, which was recognized recently and characterized by systemic proliferation of tumor cells including skin, lymph node, and bone marrow.

METHODS

The current study analyzed 47 patients with BNKL (27 had leukemias and 20 had lymphomas). Patient data were collected for the survey of the NK-Cell Tumor Study Group.

RESULTS

There were 33 males and 14 females, with a median age of 53 years (range, 3 months to 89 years). There were few clinicopathologic differences between the leukemia and lymphoma types. Cutaneous involvement was noted at diagnosis in 28 patients, who presented a tendency for older age of onset (median: 56 vs. 46 years, P = 0.11) than patients with noncutaneous BNKL. Cutaneous BNKL showed less frequent mediastinal involvement (4% vs. 53%, P = 0.0002) and less severe thrombocytopenia (P =0 .03). Phenotypic characteristics were also different, with cutaneous BNKL favoring CD4 and HLA-DR expression, and noncutaneous BNKL favoring CD16 and CD34 expression. Both groups responded well to chemotherapy for lymphoid malignancies, but disease recurrence was frequent. The prognosis of patients with noncutaneous BNKL was significantly poorer than that of patients with cutaneous BNKL (median survival: 15 vs. 25 months, P = 0.02). Multivariate analysis confirmed that cutaneous involvement was a significant and independent prognostic factor for BNKL, as were age of onset and leukocyte count.

CONCLUSIONS

These findings suggested that BNKL is a heterogeneous disease and contains at least two subtypes. Although further investigations are needed to settle a marker for distinction, the presence of cutaneous involvement is a useful prognostic factor.

Immunophenotypic and molecular features, clinical outcomes, treatments, and prognostic factors associated with subcutaneous panniculitis-like T-cell lymphoma: a systematic analysis of 156 patients reported in the literature

BACKGROUND

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an uncommon type of skin lymphoma. The natural history, optimal treatment strategy, and prognostic factors associated with this malignancy are not well defined.

METHODS

The authors performed a systematic analysis of all patients with SPTCL reported on in the English-language medical literature, with emphasis on specific clinical features, experiences involving the use of radiotherapy and systemic agents, and prognostic factors predictive of treatment response and clinical outcome.

RESULTS

One hundred fifty-six patients with SPTCL were identified in the literature. Hemophagocytic syndrome (HPS) was a presenting feature in 37% of patients, and > 90% of patients required treatment at diagnosis. Prednisone was used frequently as initial therapy in patients who had less aggressive disease at presentation; however, durable complete remissions (CR) were infrequent. Anthracycline-based chemotherapy regimens were the most commonly used and most effective systemic treatment options, producing long-term CR in approximately 30% of patients. Among patients who received high-dose chemotherapy and stem cell transplantation (HDT-SCT) for refractory or recurrent disease, 92% achieved CR, with a median response duration of > or = 14 months. The presence of HPS at diagnosis and expression of the gamma/delta T-cell receptor (TCR) by tumor cells were associated with poor survival, whereas age was not. After a median follow-up of 24 months, 48% of patients died of disease. The median survival duration was 27 months.

CONCLUSIONS

SPTCL has an aggressive natural history. Nonetheless, a subgroup of patients with SPTCL can have long-term disease remission following anthracycline-based initial therapy or subsequent HDT-SCT. HPS and the TCR phenotype may be useful prognostic markers for patients with this malignancy.

CD56+ hematological neoplasms presenting in the skin: a retrospective analysis of 23 new cases and 130 cases from the literature

BACKGROUND

The aim of this study was to define prognostic parameters and guidelines for diagnosis and treatment for CD56+ hematological neoplasms with first presentation in the skin.

PATIENTS AND METHODS

The study group included 153 cases (23 new and 130 from the literature). According to the World Health Organization classification, the group included 15 nasal and 38 nasal-type natural killer (NK)/T-cell lymphomas, 63 blastic NK-cell lymphomas, 14 cutaneous CD30+ lymphoproliferations, 10 cases of myeloid leukemia, six cases of subcutaneous panniculitis-like T-cell lymphoma (SCPLTCL) and seven peripheral T-cell lymphomas, unspecified.

RESULTS

In general, these CD56+ hematological neoplasms had a poor prognosis, with only 27% of patients alive after a median follow-up of 12 months. The median survival was 13 months. Nasal and nasal-type NK/T-cell lymphomas and CD56+ SCPLTCL had the worst prognosis, with a median survival of 5, 6 and 5 months, respectively. Only nasal-type NK/T-cell lymphomas presenting with only skin lesions had a somewhat better prognosis (median survival 27 months). In blastic NK-cell lymphomas (median survival 14 months), age </=40 years, aggressive treatment with acute leukemia protocols and high TdT expression were associated with a more favorable prognosis. Striking similarities in histology, immunophenotype, clinical presentation and clinical behavior were found between blastic NK-cell lymphomas and CD56+ myeloid leukemias.

CONCLUSIONS

CD56+ hematological neoplasms presenting in the skin have a poor prognosis, except for primary cutaneous CD30+ lymphoproliferations. The striking similarities between blastic NK-cell lymphomas and CD56+ myeloid leukemias presenting in the skin provide a rationale to treat these patients with more aggressive regimens, rather than with CHOP(-like) regimens and radiotherapy, which have proven to be inadequate therapies for this neoplasm.

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

A new group of subcutaneous, natural killer (NK), NK/T-cell, and other cytotoxic T-cell lymphomas of the skin has been recently described, and some have been included as distinct clinicopathologic entities in the classification of hematologic malignancies recently proposed by the World Health Organization. In the European Organization for Research and Treatment of Cancer classification for cutaneous lymphomas, they would be classified either as CD30- large T-cell lymphoma, small/medium pleomorphic T-cell lymphoma, or subcutaneous T-cell lymphoma. Precise clinicopathologic and prognostic features of all of them have not yet been well characterized. We studied retrospectively 81 biopsies from 50 patients with subcutaneous, blastic natural killer (NK), NK/T-cell, or other non-mycosis fungoides cytotoxic T-cell lymphomas of the skin. Clinical, morphologic, phenotypical, and genetic features and data on Epstein-Barr virus association allowed us to classify our cases according to the following 7 categories: a) subcutaneous "panniculitis-like" T-cell lymphoma (SPTCL): 10 cases (estimated 5-year survival: 80%); b) blastic NK-cell lymphoma: 12 cases (estimated 5-year survival: 0%); c) nasal-type extranodal NK/T-cell lymphoma: 5 patients (estimated 5-year survival: 0%); d) epidermotropic CD8+ T-cell lymphoma: 5 cases (estimated 5-year survival: 0%); e) cutaneous gamma/delta T-cell lymphoma: 8 cases (estimated 5-year survival: 0%); f) cutaneous alpha/beta pleomorphic T-cell lymphoma: 8 cases (estimated 5-year survival: 0%); and g) cutaneous medium/large pleomorphic T-cell lymphoma, not otherwise specified: 2 cases. Our study shows that these cutaneous lymphomas can be classified according to precise diagnostic categories. With the exception of SPTCL, analysis of follow-up data from our patients showed that these groups of lymphomas are characterized by an aggressive course, regardless of the diagnostic category.

Nodal and Extranodal Tumor-forming Accumulation of Plasmacytoid Monocytes/Interferon-producing Cells Associated With Myeloid Disorders

Nodal tumor-forming accumulations of plasmacytoid monocytes/interferon-producing cells (PMs/IPCs) have been described in patients with myeloproliferative disorders. Here we report a series of 9 additional cases of such association. The patients were predominantly adult (median, 62 years), males (male/female ratio, 7:2), who presented with chronic myelomonocytic leukemia (4 cases), acute myeloid leukemia (1), acute monocytic leukemia (2), unclassifiable chronic myeloproliferative (1), or myeloproliferative/myelodysplastic disease (1). The prognosis was poor (median survival, 24 months) and related to progression of the underlying myeloid neoplasm. We found that in addition to lymph nodes, PMs/IPCs accumulated to bone marrow (8 cases) and skin (4 cases). Immunohistochemical markers typically expressed by PMs/IPCs (CD68, CLA/HECA452, CD123) were found in all cases and shown useful to identify cells with variations from classic morphology. In addition, PMs/IPCs expressed the interferon-alpha (IFN-alpha) inducible protein MxA, the B-cell oncogene TCL1, and granzyme B. The biologic and clinical significance of the association between PMs/IPCs and myeloid disorders remains not clarified. Using fluorescence in situ hybridization analysis in a case known to harbor monosomy 7 in the myeloid leukemia, we demonstrated that PMs/IPCs share the same chromosomal abnormality, thus indicating that they are clonal, neoplastic in nature, and closely related to the associated myeloid tumor. Recently, a novel CD56+ hematologic neoplasm has been reported and retained to stem from PMs/IPCs. The majority of PMs/IPCs in the present series failed to express CD56, thus indicating that variants of PMs/IPCs neoplasms exist, which might represent parts of a spectrum.

Atypical lymphocytic lobular panniculitis

BACKGROUND

Although subcutaneous T-cell lymphoma (SCTCL) is considered an aggressive form of lymphoma, some patients manifest a long waxing and waning phase unaccompanied by constitutional symptoms.

METHODS

Twelve patients were prospectively encountered, presenting with a lymphocytic panniculitis accompanied by lymphoid atypia, although not fulfilling criteria for SCTCL. Clinical, histologic, phenotypic, and genotypic analyses were conducted.

RESULTS

There were five men, one boy, and six women; none had symptoms compatible with lupus erythematosus or aggressive SCTCL. All but two had a waxing and waning course of years. Four patients had periodic cytopenias accompanied by fevers. While responding somewhat to prednisone, the lesions relapsed. In one patient, treatment with alemtuzumab (CAMPATH-1) led to complete lesional resolution with no recurrence. Light microscopy showed expansion of the interstices of the fat lobule by mildly atypical lymphocytes of the CD4 subset in 10 biopsies from eight patients; in the other four patients, there was an increase in CD8 lymphocytes. There was diminished expression of CD5 and/or CD7 in the majority of biopsies. Ten of 13 biopsies showed clonal T-cell receptor-gamma rearrangements.

CONCLUSIONS

We apply the term atypical lymphocytic lobular panniculitis to this distinctive form of lymphocytic panniculitis manifesting this light microscopic, phenotypic, and genotypic profile.

B lineage-specific regulation of V(D)J recombinase activity is established in common lymphoid progenitors

Expression of V(D)J recombinase activity in developing lymphocytes is absolutely required for initiation of V(D)J recombination at antigen receptor loci. However, little is known about when during hematopoietic development the V(D)J recombinase is first active, nor is it known what elements activate the recombinase in multipotent hematopoietic progenitors. Using mice that express a fluorescent transgenic V(D)J recombination reporter, we show that the V(D)J recombinase is active as early as common lymphoid progenitors (CLPs) but not in the upstream progenitors that retain myeloid lineage potential. Evidence of this recombinase activity is detectable in all four progeny lineages (B, T, and NK, and DC), and rag2 levels are the highest in progenitor subsets immediately downstream of the CLP. By single cell PCR, we demonstrate that V(D)J rearrangements are detectable at IgH loci in ∼5% of splenic natural killer cells. Finally, we show that recombinase activity in CLPs is largely controlled by the Erag enhancer. As activity of the Erag enhancer is restricted to the B cell lineage, this provides the first molecular evidence for establishment of a lineage-specific transcription program in multipotent progenitors.

Histopathology and genetics of cutaneous T-cell lymphoma

There is emerging evidence that genomic and chromosomal instability are features of CTCL, including variants such as MF, Sézary syndrome, and primary cutaneous CD30+ LCAL, and that specific chromosomal abnormalities are common. Additional resolution of specific regions of chromosomal loss and gain are required to define putative genes that may be of fundamental pathogenetic importance in CTCL. Inactivation of well-defined cell cycle and TSG are common as for other types of NHL. The prognostic significance of these abnormalities in CTCL has yet to be determined. The dysregulation of specific transcription factors is of interest, but requires further study. It is hoped that greater understanding of these molecular abnormalities will permit the development of CTCL-specific therapies that alleviate suffering and prolong survival.