Agranular CD4+ CD56+ CD123+ hematodermic neoplasm (blastic NK-cell lymphoma) revealed by cutaneous localization: 2 cases

BACKGROUND: Agranular CD4+ CD56+ hematodermic neoplasm (blastic NK-cell lymphoma) has been recently described. The skin is often the first organ involved. OBSERVATIONS: Two old men of respectively 70 and 77 years consulted for infiltrated cutaneous lesions. Preliminary histological examination of cutaneous biopsy taken in both patients showed a malignant proliferation suggesting a cutaneous lymphoma, and the patients were referred. Histological examination of new biopsies showed a very similar proliferation in the 2 cases of monotonous medium-sized mononuclear cells without expression of the common antigens CD3 and CD20 and the expression of CD4, CD56, and CD123. No rearrangement of the T-cell receptor gene or the immunoglobulin heavy chain gene were evidenced. No extracutaneous involvement was initially detected in the first patient. Thrombocytopenia associated with the abnormal presence of 15 p. 100 of circulating CD4+ CD56+ cells was initially found in the second patient. The first patient was treated with chemotherapy, with complete remission. A cutaneous relapse promptly occurred, followed by bone and cerebral localizations. The patient died one year after the diagnosis of the disease, in spite of intensification of the treatment. Treatment is still ongoing in the second patient. COMMENTS: The histological presentation of these two patients was very similar with an unusual phenotype of tumor cells expressing CD4, CD56, CD123, but not expressing CD3 and CD20. Some cases have been published under the "term of blastic NK lymphoma" which is the actual term for the disease in the WHO classification. However, the tumor cells derive from the dendritic plasmacytoid cells, also called type 2 dendritic cells, and perhaps from a common precursor to lymphocyte T and dendritic plasmacytoid cells. In spite of complete cutaneous response in the 2 cases presented, as in other reports, extra-cutaneous involvement occurs quickly. Overall survival is usually poor since nearly all the patients died in less than 3 years. This justifies attempting aggressive protocols, with bone marrow allograft in the younger patients.     

Agranular CD4+ CD56+ hematodermic neoplasm: a new case report

BACKGROUND: "Agranular CD4+ CD56+ hematodermic neoplasm" are rare hematologic neoplasms which were recently shown to correspond to the plasmocytoid dendritic cells. CASE REPORT: A 83-year-old presented isolated skin lesions purple, infiltrating the dermis. The biopsy has shown a dense dermal infiltration with malignant cells CD4+ CD56+ CD43+. There were no bone marrow involvement and no circulating blood cells. A chemotherapy permitted a clinical remission after six courses. Unfortunately, skin and blood relapses appear four months later. After a short success of chemotherapy by DHAP, the patient died three month later. DISCUSSION: "Agranular CD4+ CD56+ hematodermic neoplasm" is a distinct entity from the cutaneous primary lymphomas. Recently plasmocytoid monocyte cells have been identified as the precursor of the malignant population with the high expression of CD123, IL3 receptor. It is a distinct clinicopathologic entity by its clinical presentation with skin tropism, bone marrow involvement with or without leukemic phase and poor prognosis independent of the kind of treatment and its particular phenotype CD4+ CD56+ CD43+. It would be interesting to use antibodies linked to CD123 in therapeutic because any treatment have efficacity in this disease.     

CD56+ lymphoma with skin involvement: clinicopathologic features and classification

BACKGROUND: Extranodal lymphomas expressing CD56 (neuronal cell adhesion molecule) are characterized by a high incidence of cutaneous involvement and a very aggressive clinical course. Knowledge about the prognosis and clinicopathologic features of CD56(+) lymphomas with skin involvement is very limited. OBJECTIVES: To determine survival and prognostic factors for extranodal CD56(+) lymphomas with skin involvement and to describe their clinicopathologic features. DESIGN: Retrospective literature survey and case studies. PATIENTS: A total of 181 patients with CD56(+) lymphoma involving the skin: 177 cases from the literature and 4 new cases. MAIN OUTCOME MEASURE: Survival and its dependence on the following putative prognostic factors: staging, histopathologic findings, lymphocyte markers, T-cell receptor gene rearrangement, Epstein-Barr virus infection, treatment modality. RESULTS: Three major subtypes of CD56(+) lymphoma in the skin were distinguished: blastic lymphoma, nasal-type natural killer-cell/T-cell lymphoma, and subcutaneous panniculitislike lymphoma. The disease disseminated readily, mainly to lymph nodes, bone marrow, the central nervous system, and the liver, but 45% of patients had a purely cutaneous disease at presentation. All subtypes had a very aggressive course with a median survival of 14 months. The main risk factors were age older than 55 years (hazard ratio [HR], 2.5; 95% confidence interval [CI], 1.8-3.2), systemic dissemination at presentation (HR, 2.0; 95% CI, 1.5-3.3), and lack of CD30 (HR, 3.8; 95% CI, 1.4-4.9) or CD4 expression (HR, 1.56; 95% CI, 1.06-2.57). The different treatment modalities did not improve survival. CONCLUSIONS: CD56(+) lymphomas involving the skin are rare and extremely aggressive regardless of their histologic presentation and the extent of skin involvement. No effective treatment is available. The risk of death is particularly increased in older patients with CD30(-)CD4(-) lymphomas.     

CD56-positive cutaneous lymphoma: a poorly recognized entity in the spectrum of primary cutaneous disease

CD56-positive (CD56+) lymphomas, characterized by the expression of the neural cell adhesion molecule on pathological lymphocytes, share a frequent extranodal involvement and a generally aggressive course. Five CD3- CD56+ lymphoma patients presenting with nodular lesions were identified among 180 immunophenotyped cutaneous lymphomas. All the patients were men, with ages ranging from 55 to 78 years. After staging, two patients were diagnosed as having primary cutaneous lymphomas: the remaining three had the secondary cutaneous type. The clinical course was aggressive and four patients died within 8 months from diagnosis. The remaining patient is still alive after a 17-month follow-up. The histological diagnosis was immunoblastic lymphoma in two patients, and medium and large cell pleomorphic lymphoma in three. The angiocentric infiltrate was located mainly in the dermis: azurophilic granules were present in three of the five patients. Immunogenotypic analyses suggested the natural killer cell origin of these neoplasias: all cases exhibited a CD56+ CD3- CD5- T-cell receptor (TCR) silent phenotype, and Southern blot analysis showed a germline configuration of the TCR β-chain gene.     

TCR gene-rearranged,extranodal NK/T-cell lymphoma,nasal type,presenting as gyrate patches

In the CD56+ cutaneous nasal-type NK/T-cell lymphoma strongly associated with latent EBV infection, subcutaneous or dermal nodules are the most common skin findings, but great morphologic heterogeneity has been noted including papules, infiltrated plaques, and ulcerated tumors, and TCR genes are mostly germline. We describe a case of nasal and nasal-type NK/T-cell lymphoma featuring multiple erythematous polycyclic patches on the trunk, which is similar to patch stage mycosis fungoides or other cutaneous T cell lymphoma. Immunohistochemical study of a skin biopsy specimen revealed CD2+, CD3epsilon+, CD56+, and CD45RO+ expression in the neoplastic cells. In situ hybridization using an anti-sense Epstein Barr virus early regions probe showed a positive reaction. However, clonal TCR beta gene rearrangement was found.     

CD4+/CD56+ hematodermic neoplasm: report of a rare variant with a T-cell receptor gene rearrangement

CD4+/CD56+ hematodermic neoplasm (HN), formerly known as a blastic natural killer (NK) cell lymphoma, is a rare subtype of a cutaneous dendritic cell neoplasm notable for highly aggressive behavior. The characteristic features are: expression of the T-helper/inducer cell marker CD4 and the NK-cell marker CD56 in the absence of other T cell or NK-cell specific markers. In particular, CD3 (surface or cytoplasmic) and CD2 are not expressed. Although T-cell receptor (TCR) genes are generally reported to be in a germline configuration, we present an unusual variant of a CD4+/CD56+ HN with a clonal rearrangement of TCR genes. This feature of a CD4+/CD56+ HN has been only rarely reported. Recognition of the presence of clonal TCR gene rearrangements in a small subset of CD4+/CD56+ HN is important to avoid misdiagnosis of this entity as an unusual variant of a cutaneous T-cell lymphoma.     

Cutaneous tumors as the initial presentation of non-T, non-B, nonmyeloid CD4+ CD56+ hematolymphoid malignancy in an adolescent boy

We describe a 14-year-old Hispanic boy who presented with a 2-month history of enlarging plum-colored cutaneous tumors on his face, trunk, and proximal extremities. Histopathologic examination showed nodular infiltrates of malignant mononuclear cells extending from the superficial dermis to the deep subcutis. Immunohistochemical staining of the biopsy specimen and flow cytometry studies on a bone marrow aspirate revealed a CD4+, CD56+ hematolymphoid tumor that was negative for all other myeloid and lymphoid markers. Based on this information, the patient was diagnosed with the recently described, rare non-T, non-B, nonmyeloid CD4+ CD56+ hematolymphoid malignancy. To our knowledge, this is the youngest patient reported in the literature.     

Skin manifestations in CD4+, CD56+ malignancies

CD4+ CD56+ hematologic neoplasms were recently individualized. We report three cases of CD4+ CD56+ malignancies with cutaneous lesions in three cases and also bone marrow involvement in two cases. Two patients relapsed 2 and 3 months after polychemotherapy. Two patients died within 3-10 months. A constant immunophenotype was observed with the co-expression of CD4 and CD56, the absence of B and T-cell markers. The salient fact of this report is the presence of T-cell clonal rearrangement. The clinical and pathological features closely resemble the specific cutaneous manifestations in acute leukemia with monocytic differentiation, especially the granulocytic sarcoma. Because of the positivity of the CD56, natural killer cell proliferations were discussed. Since 1994, 50 cases of CD4+, CD56+ cutaneous neoplasms have been reported with specific clinical, cytologic and immunohistochemical features. The diagnosis is more difficult when the cutaneous location is exclusive; on the contrary, the cytological features of the blood and medullar cells with cytoplasmic vacuoles and pseudopodia are characteristic of this hematologic neoplasm. The presence of CD123 antigen in most of the cases is an argument for a plasmacytoid dendritic cell proliferation and it is also a good marker for primary cutaneous lesions.     

Haematodermic CD4+CD56+ neoplasm: complete remission after methotrexate–asparaginase treatment

Haematodermic neoplasm is a recently recognized condition, characterized by tumour cells expressing CD4, CD56 and CD123. This phenotype is strongly suggestive of a plasmacytoid dendritic cell origin. This haematopoietic malignancy is a distinct clinicopathological condition with frequent skin involvement, an evolution toward leukaemia and a rapidly aggressive course. We report the case of a 64-year-old woman who presented with a haematodermic CD4+CD56+CD123+ neoplasm affecting the left cheek; the initial staging was otherwise negative. Despite this early stage of the disease, aggressive treatment including methotrexate–asparaginase and local radiotherapy was proposed as first-line therapy. Complete clinical remission was rapidly reached and the patient was still alive after > 30 months of follow-up. To date there is no consensus on the first-line treatment for such patients but intensive treatment is probably needed immediately even in cases of localized disease. The response obtained with CHOP (cyclophosphamide, doxyrubicin, vincristine, prednisone) or CHOP-like chemotherapy regimens is disappointing. Other regimens, such as those used in acute leukaemia, may improve the outcome of these patients.     

Cutaneous involvement by angioimmunoblastic T-cell lymphoma with remarkable heterogeneous Epstein-Barr virus expression

INTRODUCTION: Initially described as an abnormal immune reaction, most cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like T-cell infiltrates are now regarded as a peripheral T-cell lymphoma (AILD T-NHL). AILD T-NHL is characterized clinically with constitutional symptoms, generalized lymphadenopathy, hepatosplenomegaly, skin rash, and polyclonal hypergammaglobulinemia. Epstein-Barr virus (EBV) is frequently detected in involved lymph nodes, but the presence of EBV in cutaneous infiltrates of AILD T-NHL has rarely been examined. We present a patient with AILD T-NHL with cutaneous involvement that shows marked heterogeneity of EBV expression in the lymph node and skin biopsies, and review the histological findings of AILD T-NHL in the skin. METHODS: Two skin biopsies of a diffuse maculopapular rash and a lymph node were examined and immunophenotyped. In situ hybridization for detection of EBV in the lymph node and skin biopsies was utilized. In order to attempt to delineate which lymphocytes were EBV positive, skin biopsies were dual labeled with CD3, CD45RO, CD20 and EBV. The skin biopsies and lymph node were submitted for gene rearrangement studies by polymerase chain reaction (PCR). Capillary electrophoresis of fluorescently labeled PCR products was utilized for PCR product quantitation. RESULTS: The histological features of the lymph node were diagnostic of AILD T-NHL and a T-cell clone was identified by PCR. The skin biopsies showed an atypical superficial and deep perivascular polymorphous infiltrate consistent with cutaneous involvement by AILD T-NHL. Both skin biopsies showed the same clonal T-cell receptor gene rearrangement as the lymph node. In situ hybridization of the lymph node and one skin biopsy showed a few scattered EBV-positive lymphocytes (<1% of the infiltrate). A second skin biopsy revealed 40-50% of the lymphocytes as EBV positive. Dual staining for CD20 and EBV identified a minority of EBV-infected lymphocytes as B-cells, but most of the EBV-positive cells lacked staining for CD3 and CD45RO. CONCLUSIONS: In our patient, the same T-cell receptor gene rearrangement was found by PCR in all three biopsy sites. Most cases of AILD T-NHL contain only a few EBV-positive cells, but in our patient the extent of EBV expression ranged from <1% to 40-50% of the AILD T-NHL cutaneous infiltrate. To our knowledge, this case is the most extensive and heterogeneous expression of EBV in cutaneous AILD T-NHL to date.     

Cutaneous involvement by colonic extranodal NK/T-cell lymphoma mimicking mycosis fungoides: a case report*

We report a 51-year-old woman with cutaneous involvement by extranodal NK/T-cell lymphoma (TCL) of the colon that microscopically mimicked mycosis fungoides (MF). She had a history of fever of unknown origin for 2 months and then developed multiple erythematous papules on her trunk and extremities. A skin biopsy revealed superficial infiltration by atypical small to medium-sized lymphocytes with epidermotropism and Pautrier collections. Immunohistochemical studies showed expression of CD3 and TIA-1 with lack of expression (double negative) of CD4 and CD8. Initially, we reported the diagnosis as MF, cytotoxic variant. Thereafter, computerized tomography scan incidentally identified a colonic mass. A colonic biopsy revealed infiltration of atypical lymphoid cells with the same morphology and immunophenotype as those found in the skin. Additionally, CD56 and Epstein-Barr virus-encoded RNA in situ hybridization in both skin and colonic biopsies were diffusely positive. Thus, extranodal NK/TCL was diagnosed. Delta T-cell receptor (TCR) gene rearrangement was documented in the skin biopsy by polyacrylamide gel electrophoresis and fluorescence capillary gel electrophoresis methods. There was no TCR gene rearrangement detected in the colonic biopsy. Unfortunately, the patient died within 2 months of diagnosis.     

A case of primary cutaneous CD30+ T-cell lymphoproliferative disorder with features of granulomatous slack skin disease

We present a patient with primary CD30+ cutaneous T-cell lymphoma whose histological and clinical features overlapped with those of granulomatous slack skin disease (GSSD). A 26-year-old woman had infiltrative erythema on the abdominal wall and an incurable ulcerative lesion on the left knee. Her skin progressively became atrophic and pendulous, showing a hyperpigmented appearance over almost the whole body. Histopathologically, a dense lymphoid cell infiltrate accompanying numerous macrophages and multinucleated giant cells (MGC) extended into the subcutaneous tissue. Most lymphoid cells were small and positive for T-cell markers. Some relatively large atypical cells were scattered in the lesion, most of which (60%) were positive for CD30. T-cell receptor-beta gene rearrangement was confirmed in the abdominal lesion. MGC infiltrated more dominantly into a deeeper layer of the skin with the elastic fibres there almost completely disappearing. Immunoreactivity for CD30 of MGC was negative and overexpression of elastolytic metalloproteinases was observed. The association between primary cutaneous CD30+ lym- phoproliferative disorders and GSSD has not previously been reported. Overexpression of elastolytic metalloproteinases in MGC contributes to the disappearance of the elastic fibres and enhances the severity of the clinical course.     

Cutaneous peripheral T-cell lymphoma of cytotoxic phenotype mimicking extranodal NK/T-cell lymphoma

Cutaneous peripheral T-cell lymphoma unspecified is a rare neoplasm that is infrequently associated with Epstein-Barr virus (EBV) infection. In contrast, extranodal natural killer (NK)/T-cell lymphoma, although also rare, is known to be strongly associated with EBV and occurs most commonly in the nasal region. We report the case of a 55-year-old male who presented with fever and an indurated cutaneous plaque with ulceration. This cutaneous neoplasm showed diffuse dermal lymphomatous infiltration and tumor necrosis, with neoplastic cells expressing CD2, cytoplasmic CD3 (CD3ε), CD8, CD16, CD30, T-cell intracellular antigen-1, and granzyme B but not CD56, BF1, or T-cell receptor (TCR) δ1. Furthermore, the tumor cells were noted to be diffusely positive for EBV by in situ hybridization. A monoclonal TCR gene rearrangement was demonstrated. The disease showed an aggressive clinical course, and the patient died within 3 weeks of diagnosis without complete staging or chemotherapy. According to the 2005 World Health Organization/European Organization for Research and Treatment of Cancer scheme for cutaneous lymphoma and the 2008 WHO classification for lymphoid neoplasms, our case would have been classified as a nasal type extranodal NK/T-cell lymphoma with T-cell lineage. However, the expressions of CD8 and CD16, in addition to a monoclonal TCR gene rearrangement, are unusual findings in NK/T-cell lymphoma, and we believe such a phenotype/genotype should be more appropriately classified as an EBV-positive peripheral T-cell lymphoma, unspecified with a cytotoxic phenotype. Detailed clinicopathologic and molecular studies of similar cases may shed light on the prognostic impact of NK vs. T-cell lineage on extranodal NK/T-cell lymphomas.     

gamma delta T-cell lymphoma of the skin: a clinical, microscopic, and molecular study

BACKGROUND: Only a few cases of primary gamma delta cutaneous T-cell lymphoma (CTCL) have been reported. We encountered 3 cases of this rare condition. OBJECTIVES: To characterize gamma delta CTCL by clinical, microscopic, and molecular methods and to investigate the role of Epstein-Barr virus (EBV) infection in its pathogenesis. DESIGN: Patients were evaluated by clinical examination, and biopsy specimens of lesional skin were examined by light microscopy and immunohistochemistry. Polymerase chain reaction amplification for T-cell receptor gamma gene rearrangements and in situ hybridization for EBV were performed on 3 biopsy specimens. SETTING: National Institutes of Health, a tertiary referral center. PATIENTS: Individuals with a clinical and histologic diagnosis of primary gamma delta CTCL. OUTCOME MEASURES: Clinical, light microscopic, and immunohistochemical features, and the presence of T-cell rearrangement and EBV RNA in biopsy specimens. RESULTS: Patients exhibited multiple plaques, tumors, and/or subcutaneous nodules primarily distributed over the extremities. Individuals exhibited an aggressive clinical course with resistance to multiagent chemotherapy and radiation. Microscopic examination revealed epidermotropism in 2 cases, a dermal infiltrate in all 3 cases, and subcutaneous involvement in 1 case. Immunohistochemical studies showed the presence of CD3(+)TCR delta(+) in 3 patients, CD8(+)in 1, and CD4(+), CD20(+), CD56(+), and beta F1(+) in none. All 3 cases exhibited an activated cytotoxic T-cell phenotype positive for T-cell intracellular antigen 1, perforin, and granzyme B. A clonal T-cell receptor gamma chain gene rearrangement was detected in all 3 cases by polymerase chain reaction. In situ hybridization was negative for EBV sequences in all 3 cases. CONCLUSION: gamma delta Cutaneous T-cell lymphomas are EBV-negative lymphomas that express a mature cytotoxic phenotype and have an aggressive clinical behavior. Arch Dermatol. 2000;136:1024-1032     

Unlikely role of Epstein-Barr virus in the pathogenesis of primary cutaneous CD30+ anaplastic large cell lymphoma

BACKGROUND: Primary cutaneous CD30+ anaplastic large cell lymphoma (ALCL) is a rare subset of cutaneous lymphoma, with a much better prognosis than its nodal counterpart. The pathogenesis of both nodal and primary cutaneous CD30+ ALCL is largely unknown but experimental data support the hypothesis that the Epstein-Barr virus could play a role in the nodal subset. OBJECTIVE: To evaluate the involvement of Epstein-Barr Virus (EBV) in primary cutaneous CD30+ ALCL by searching for both nucleic acids and EBV proteins in cutaneous lesions. SETTING: Two University Hospitals in Southern France (secondary referral hospitals). PATIENTS: Eight consecutive patients with typical primary cutaneous CD30+ anaplastic large cell lymphoma were studied. METHODS: Search for the presence of DNA, RNA and EBV proteins in cutaneous lesions by PCR, in situ hybridization and immunohistochemistry. RESULTS: EBV DNA and RNA was identified in only one lesion of primary cutaneous CD30+ ALCL and in none of the normal adjacent skin samples. In situ hybridization and immunohistological studies were consistently negative in all samples. Conclusion: These results do not support an early role of EBV in the oncogenetic pathogenesis of primary cutaneous CD30+ ALCL.     

Blastic natural killer cell and extranodal natural killer cell-like T-cell lymphoma presenting in the skin: report of six cases from the UK

BACKGROUND: Some lymphomas express natural killer (NK)-cell markers such as the neural cell adhesion molecule, which is recognized by the CD56 antibody. These lymphomas may present in the skin, but do not represent a homogeneous group. The new World Health Organization classification of lymphoma/leukaemia recognizes several types of NK/T-cell neoplasm, including blastic NK-cell lymphoma, which characteristically presents with cutaneous lesions. OBJECTIVES: To describe the clinical, pathological and molecular features in six cases of CD56+ lymphoma with cutaneous presentation. METHODS: The clinical, histopathological and immunophenotypic features of six patients were reviewed. In addition, in situ hybridization (ISH) to identify Epstein-Barr virus (EBV) mRNA, and polymerase chain reaction analysis to identify the presence of a clonal population of T cells or B cells were performed on lesional skin. RESULTS: All patients presented with widespread nodules and plaques, which in five cases were a characteristic purple colour. Four patients developed disseminated disease, three with neurological involvement. These four patients died between 14 and 46 months following diagnosis (median 30 months). In four of six cases the histopathological and immunohistological features were in keeping with a blastic NK-cell lymphoma. No clonal immunoglobulin heavy chain (IgH) or T-cell receptor (TCR) gene rearrangement was detected in the four cases consistent with an origin from NK cells. A further case fitted the criteria for an extranodal NK/T-cell lymphoma of nasal type and was also the only case to show evidence of EBV mRNA by ISH. A clonal T-cell population was identified in the final case. This patient also exhibited molecular evidence of a clonal B-cell population and a t(14;18) translocation confirmed by sequence analysis. CONCLUSIONS: Our data confirm that NK-cell lymphomas presenting in the skin are a heterogeneous group, and that in the U.K., blastic NK-cell lymphoma is more common than extranodal NK/T-cell lymphoma of nasal type. These lymphomas pursue an aggressive course, with rapid development of disseminated disease, and resistance to chemotherapy. Detailed immunophenotyping is needed to distinguish the different types. Our molecular data indicate that blastic NK-cell lymphoma cases lack clonal TCR/IgH gene rearrangements consistent with an NK-cell origin. Our ISH findings indicate that EBV plays a pathogenetic role only in extranodal NK/T-cell lymphoma of nasal type.     

An Unusual Hematologic Malignancy Derived from Plasmacytoid Dendritic Cells

Recently reported cases of CD4+ CD56+ hematologic malignancies with a strong predilection for the skin correspond to the neoplastic counterpart of plasmacytoid dendritic cells. This rare, aggressive malignancy lacks pan‐myeloid and pan‐lymphoid markers and often presents with cutaneous lesions, splenomegaly, and involvement of lymph nodes and bone marrow. It has a poor prognosis, and many patients progress to acute myeloid leukemia. The proposed cellular origin is a CD56+ precursor cell related to plasmacytoid monocytes, which strongly expresses CD123 (IL‐3Ra). We describe a 70 year‐old man who presented with gray‐brown truncal nodules and plaques, lymphadenopathy, and splenomegaly. His bone marrow demonstrated malignant CD4+ CD56+ mononuclear cells. Histologic sections of skin lesions showed an atypical infiltrate extending into the deep reticular dermis. Immunohistochemical staining of these cells for CD4 was diffusely positive. Moreover, the infiltrate strongly expressed CD56 and CD123 but showed only patchy or negative staining for other T and B cell markers. The combination of the patient's clinical presentation and biopsy results best fits the diagnosis of this newly characterized, distinct clinicopathologic entity described in recent literature as agranular CD4+ CD56+ hematodermic neoplasm, plasmacytoid dendritic cell acute leukemia, and tumor‐forming accumulations of plasmacytoid monocytes associated with myeloid disorders.     

Specific skin manifestations in CD56 positive acute myeloid leukemia

We found 16 CD56+ cases (29.6%) among 54 acute myeloid leukemia (AML) patients; they showed significantly frequent cutaneous involvement compared to CD56- cases (43.8% vs. 15.8%, p<0.05). Four of the CD56+ AML cases with specific skin manifestations were reviewed histologically. In all cases, cutaneous leukemic cells were seen in the dermis and subcutaneous tissue with accentuation around the adnexa/nerve, but sparing the epidermis. In addition, angiocentric/ angiodestructive and prominent cohesive tumor cell growth were seen in two cases, respectively. These findings suggest that the expression of CD56 may often be associated with the cutaneous involvement in AML, and that the above histological findings should remind us of the possibility of specific skin manifestations in CD56+ AML.     

CD4+/CD56+ haematodermic neoplasm: a preculsor haematological neoplasm that frequently first presents in the skin

CD4+/CD56+ hematodermic neoplasm, formerly known as blastic NK cell lymphoma, is an aggressive and rare preculsor hematologic neoplasm recently recognized by the WHO-EORTC classification consensus for cutaneous lymphomas. The neoplasm tends to affect elderly patients, who usually present with skin lesions but often have a disseminated disease, including bone marrow involvement. Although the lesions are composed of cells with a lymphoblast-like morphology and an NK-cell phenotype, exhibiting a CD4+, CD56+ positive immunophenotype, recent studies support a relationship to plasmacytoid dendritic cells. Because of the rarity of this disease, we describe two patients suffering a CD4+/CD56+ hematodermic neoplasm.