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

T-cell/NK-cell lymphomas: A review

T-cell neoplasms are a group of heterogeneous neoplasms that present a challenge in management. Accurate diagnosis and classification are necessary for proper treatment. This dilemma is exemplified by continuous upgrading of classification systems in an effort to better understand these diseases. The spectrum of management varies from observation and monitoring to prompt aggressive multimodality treatment to achieve optimal outcomes. Allogeneic transplant has been successful in a minority of cases with the possibility of cure; however this approach is still largely experimental. Molecular studies such as gene expression profiling are expected to offer exciting insight into the biology of these diseases. Novel therapeutic approaches continue to be explored, however will probably require larger clinical trials to establish their utility over the current standard.

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.

Cutaneous γ/δ T-cell lymphoma: A histopathologic mimicker of lupus erythematosus profundus (lupus panniculitis)

In the newly revised World Health Organization (WHO)-European Organization for Research and Treatment of Cancer (EORTC) consensus classification for cutaneous lymphomas, cutaneous gamma/delta T-cell lymphoma (CGD-TCL) has been included as a provisional entity. This type of lymphomas, when involving the subcutaneous fat, can mimic both clinically and histologically other more indolent conditions, such as subcutaneous panniculitic T-cell lymphomas (SPTCL) and lupus erythematosus profundus (LEP), and multiple biopsies may be needed to obtain a correct diagnosis. A good correlation of the clinical data with the histopathology and immunohistochemistry are required for diagnosis. Herein, we describe a patient whose initial histopathologic findings ressembled LEP but presented an aggressive clinical course. A new biopsy was performed during the follow-up, and a final diagnosis of CGD-TCL was made.

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.

Agranular CD4+/CD56+ Hematodermic Neoplasm: A Distinct Entity Described in the Recent World Health Organization–European Organization for Research and Treatment of Cancer Classification for Cutaneous Lymphomas

Agranular CD4+/CD56+ hematodermic neoplasm is a distinct form of lymphoma with aggressive behavior and marked predilection for cutaneous involvement. Because of CD56 positivity, natural killer cells were initially suggested as the cell of origin in this tumor. In the recent World Health Organization–European Organization for Research and Treatment of Cancer classification, the term blastic natural killer cell lymphoma has been replaced with CD4+/CD56+ hematodermic neoplasm because of its derivation from a plasmacytoid dendritic cell precursor. Clinicopathologic features, immunohistochemical features, and differential diagnosis of this rare neoplasm with emphasis on the recent World Health Organization–European Organization for Research and Treatment of Cancer classification are discussed.

Expression of the plasmacytoid dendritic cell marker BDCA-2 supports a spectrum of maturation among CD4+ CD56+ hematodermic neoplasms

CD4+CD56+ hematodermic neoplasms are rare, aggressive hematopoietic malignancies usually presenting with cutaneous masses followed by a leukemic phase. The blastic morphology, CD56 expression and lack of definitive myeloid or T-cell markers initially resulted in assignment of this tumor to the NK-cell lineage. Accumulating evidence now suggests that these neoplasms represent malignant counterparts to the plasmacytoid dendritic cell. BDCA-2 is a cell surface protein whose expression is restricted to human plasmacytoid dendritic cells, in a differentiation stage-specific manner. In the current study, we assessed expression of BDCA-2 in CD4+CD56+ hematodermic neoplasms using a new antibody reagent we developed for use in fixed tissue sections. In 10 of 19 cases of CD4+CD56+ hematodermic neoplasm, BDCA-2 immunoreactivity was detected, whereas no expression was observed in NK-lineage tumors (0 of six). Interestingly, expression of terminal deoxynucleotidyl transferase, a marker of immaturity/blast stage, was significantly and negatively correlated with BDCA-2 in CD4+CD56+ hematodermic neoplasms whereas a positive correlation was observed between BDCA-2 and CD7. These findings demonstrate that BDCA-2 is expressed predominantly in the CD7+ subset of hematodermic neoplasms, and similar to non-neoplastic plasmacytoid dendritic cells, expression indicates a relatively more mature differentiation state. Clinical follow-up data confirm the aggressiveness of these tumors and suggests that BDCA-2 immunoreactivity, as identified here, may herald a significant reduction in survival.

Extranodal NK/T-cell lymphoma, nasal type

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL), previously known as lethal midline granuloma is a distinct clinico-pathological entity associated with Epstein-Barr virus that typically causes destruction of the midface, palatal and orbital walls. In addition, ENKTCL can involve the skin, soft tissue, testes, gastrointestinal and upper respiratory tract. ENKTCL neoplastic cells express some T-cell associated antigens, most commonly CD2 and cytoplasmic CD3epsilon and, in favour of an NK-cell origin, CD56. Early stage disease may respond to radiotherapy alone, however late stage disease does not respond well to any available therapies. Overall, patients with ENKTCL have a cumulative probability of survival at 5 years ranging from 37.9% to 45.3%.

Lymphoproliferative lesions of the skin

Diagnosis and differential diagnosis of cutaneous lymphoproliferative disorders is one of the most difficult areas in dermatopathology, and biopsies are often taken to rule out a cutaneous lymphoma in patients with "unclear" or "therapy-resistant" skin lesions. Histopathological features alone often enable a given case to be classified to a diagnostic group (eg, epidermotropic lymphomas), but seldom allow a definitive diagnosis to be made. Performing several biopsies from morphologically different lesions is suggested, especially in patients with suspicion of mycosis fungoides. Immunohistochemistry is often crucial for proper classification of the cases, but in some instances is not helpful (eg, early lesions of mycosis fungoides). Although molecular techniques provide new, powerful tools for diagnosing cutaneous lymphoproliferative disorders, results of molecular methods should always be interpreted with the clinicopathological features, keeping in mind the possibility of false positivity and false negativity. In many cases, a definitive diagnosis can be made only on careful correlation of the clinical with the histopathological, immunophenotypical and molecular features.

Pleomorphic CD8+ Small/Medium Size Cutaneous T-Cell Lymphoma

Pleomorphic small/medium-sized cutaneous T-cell lymphoma is a recently recognized rare type of cutaneous T-cell lymphoma which is clinicopathologically different from mycosis fungoides and Sezary syndrome. By definition the phenotype of the neoplastic lymphocytes in pleomorphic small/medium-sized cutaneous CD3CD4CD8 but CD8 pleomorphic small/medium sized cutaneous T-cell lymphoma cases have been occasionally described. We describe a 55-year-old female with a pruritic erythematous nodule on the lateral aspect of her right foot present for 1.5 years. Histology revealed a nonepidermotropic lichenoid infiltrate in the papillary dermis and a patchy infiltrate in the mid and lower dermis composed of small to medium-sized pleomorphic lymphocytes. The immunophenotype of these lymphocytes was CD3CD4CD8TIA-1. Staining for CD20, CD30, CD56, TdT, and LMP1 were negative, and the Ki-67 proliferation index was 5% to 10%. Gene rearrangement studies demonstrated a T-cell clone. The laboratory and imaging workup did not reveal extracutaneous involvement. The lesion was treated by local irradiation but a follow-up biopsy demonstrated only partial remission. Consequently, the lesion was treated by surgical excision.

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.

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.

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.

WHO/EORTC classification of cutaneous lymphomas 2005: histological and molecular aspects

The new WHO/EORTC classification for cutaneous lymphomas comprises mature T-cell and natural killer (NK)-cell neoplasms, mature B-cell neoplasms, and immature hematopoietic malignancies. It reflects the unique features of lymphoproliferative diseases of the skin, and at the same time it is as compatible as possible with the concepts underlying the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. This article reviews the histological, phenotypical, and molecular genetic features of the various nosological entities included in this new classification. These findings always have to be interpreted in the context of the clinical features and biologic behavior.

AIM

To review the histological, phenotypical and molecular genetic features of the various nosological entities of the new WHO/EORTC classification for cutaneous lymphomas.

METHODS

Extensive review of the literature cited in Medline and own data of the authors.

RESULTS

The WHO/EORTC classification of cutaneous lymphomas comprises mature T-cell and NK-cell neoplasms, mature B-cell neoplasms and immature hematopoietic malignancies. It reflects the unique features of primary cutaneous lymphoproliferative diseases.

CONCLUSION

This classification is as much as possible compatible with the concept of the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. The histological, phenotypical and molecular genetic features always have to be interpreted in the context of the clinical features and biologic behavior.

The New World Health Organization–European Organization for Research and Treatment of Cancer Classification of Cutaneous Lymphomas

The WHO-EORTC classification of cutaneous lymphomas is a good start to unifying nomenclature, a necessity before coherent consensus diagnoses can be made. There are three provisional diagnoses in this new classification that are not covered in detail in this review because they are rare diseases that still require further study for definitive classification. Much remains to be elucidated about cutaneous lymphomas, but understanding of the major entities within the new classification is an important first step in understanding these diverse diseases.

Fatal CD8+ Epidermotropic Cytotoxic Primary Cutaneous T-Cell Lymphoma with Multiorgan Involvement

A 70-year-old woman presented with a 3-month history of two ulcerated erythematous-violaceous nodular lesions over the nose and forehead, respectively. The patient's history included a similar cutaneous nodule on the glabella diagnosed as pseudolymphoma 2 years ago. At that time, despite the diagnosis of a benign disease, an adequate staging was performed, ruling out any extracutaneous involvement. During hospitalization, multiple purpuric papules developed over the abdomen, and the disease spread to mediastinal lymph nodes, lungs and the central nervous system. Based on the histologic, immunophenotypic and molecular biology findings, a diagnosis of CD8+ epidermotropic cytotoxic primary cutaneous T-cell lymphoma was made. Secondary skin involvement by a CD8+ extracutaneous T-cell lymphoma could not be excluded with certainty, but seemed to be unlikely because of the negativity of the initial workup. The patient died from complications of right femoral artery thrombosis before starting specific polychemotherapy 21 months after onset of the disease. Among primary cutaneous T-cell lymphomas, the CD8+ epidermotropic cytotoxic subset comprises rare, highly aggressive forms characterized by metastatic spread to unusual sites such as the oral cavity, lungs, testis and the central nervous system but usually not to the lymph nodes. These cases seem to be distinct from mycosis fungoides with CD8+ phenotype, which shows a nonaggressive clinical behavior.

T-cell non-Hodgkin lymphoma

T-cell non-Hodgkin lymphomas (NHLs) are uncommon malignancies. The current WHO/EORTC classification recognizes 9 distinct clinicopathologic peripheral T-cell NHLs. These disorders have unique characteristics and require individualized diagnostic and therapeutic strategies. Tremendous progress has been made in recent years in the understanding of the pathogenesis of these disorders. Specific chromosomal translocations and viral infections are now known to be associated with certain lymphomas. In this review, we describe their clinical and pathologic features. We also discuss the use of molecular studies in the diagnostic work-up of T-cell lymphomas. Because of the rarity of these disorders and the lack of well-designed clinical trials, the treatment of peripheral T-cell NHLs is often challenging. Additional studies are required to learn more about the biology of these diseases, which may lead to more optimal and possibly targeted therapies.

CD56 staining in Merkel cell carcinoma and natural killer-cell lymphoma: magic bullet, diagnostic pitfall, or both?

BACKGROUND

Antibodies to CD56 label natural killer (NK) cell lymphomas and neuroendocrine tumors such as Merkel cell carcinoma (MCC). In MCC altered by crush artifact or obscured by lymphocytes, the histologic features coupled with CD56 positivity can lead to an erroneous impression of NK-cell lymphoma.

METHODS

Eighteen cases of MCC were stained for CD56, CK20, MNF116, and pankeratin. The results were compared to histologic features and CD56 staining pattern of three NK-cell lymphomas.

RESULTS

Three of 18 cases of MCC histologically resembled lymphoma, and CD56 positivity with CD3 and CD20 negativity initially raised the possibility of NK-cell lymphoma. Two additional cases were obscured by dense inflammation, again suggesting the diagnosis of lymphoma. Seventeen of 18 MCC labeled for CD56 and an equal number stained for CK20. All MCC tested were positive for CAM5.2 (14/14) and MNF116 (17/17). Antibodies to pankeratin labeled only one of 18 MCC. Staining for CD56 was stronger in MCC than NK-cell lymphomas.

CONCLUSIONS

CD56 is a sensitive marker for MCC as well as for NK-cell lymphoma, but is not specific. Importantly, CD56 positivity in crushed or inflamed biopsies of MCC may lead to an erroneous impression of NK lymphoma. Awareness of this potential pitfall will prevent misdiagnosis. McNiff JM, Cowper SE, Lazova R, Subtil A, Glusac EJ. CD56 staining in Merkel cell carcinoma and natural killer-cell lymphoma: Magic bullet, diagnostic pitfall, or both?

Lupus erythematosus panniculitis (lupus profundus): Clinical, histopathological, and molecular analysis of nine cases

BACKGROUND

The diagnosis of lupus erythematosus panniculitis (LEP) may be very difficult in cases in which involvement of the subcutaneous fat is the only manifestation of the disease. The main differential diagnosis is subcutaneous panniculitis-like T-cell lymphoma (SPTCL).

METHODS

We performed a retrospective study reviewing the histopathologic features of 11 biopsy specimens from nine patients with LEP (M : F = 2 : 7; median age: 48 years; range: 20-71 years).

RESULTS

Histopathologically, all biopsies revealed a lobular panniculitis, with concomitant septal involvement in 82% of them. Dermal changes included the presence of superficial and deep infiltrates (82%) and mucin deposition (73%). The majority of cases (73%) presented also some form of epidermal involvement. The subcutaneous infiltrate was composed of lymphocytes in all cases, admixed with plasma cells in 91% of cases. Lymphoid follicles with reactive germinal centers were detected in 45% of cases. Immunohistochemistry showed a predominance of alpha/beta-T-helper and cytotoxic lymphocytes in 80% of cases admixed with B lymphocytes. The polymerase chain reaction analysis of the T-cell receptor (TCR)-gamma gene showed a polyclonal smear in all cases.

CONCLUSIONS

Our study shows that the most useful histopathologic criteria for distinguishing LEP from SPTCL are the presence of involvement of the epidermis, lymphoid follicles with reactive germinal centers, mixed cell infiltrate with prominent plasma cells, clusters of B lymphocytes, and polyclonal TCR-gamma gene rearrangement.

Role of host's antitumor immunity in exercise-dependent regression of murine T-cell lymphoma

We have reported that the ascitic growth of a transplantable T cell lymphoma of spontaneous origin, designated as Dalton's lymphoma (DL), is associated with a concomitant immunosuppression. We have also reported that progressive in vivo growth of DL resulted in an inhibition of macrophage functions. In present investigation we report that physical exercise by DL-bearing mice, on a treadmill on a daily basis for various time durations for 10 days, increased the life span along with an inhibition of tumor growth. A significant decrease in the volume of ascitic fluid and number of cells in the tumor was obtained in mice, which underwent exercise. DL cells obtained from exercised groups showed a decreased proliferation in vitro. An augmentation in the percent of cells showing apoptotic morphology and percent specific DNA fragmentation was observed, suggesting that physical exercise increased the incidence of apoptosis in tumor cells. Moreover, macrophages obtained from tumor-bearing mice, which underwent exercise training, showed an augmented tumoricidal activity and production of tumoricidal molecules like interleukin-1 (IL-1), tumor necrosis factor (TNF) and nitric oxide (NO). On the basis of this study it is suggested that the regression of tumor growth consequent to physical exercise training of tumor bearing host, may be due to an exercise-dependent augmentation of macrophage tumoricidal functions.

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.