Frequent expression of CD30 antigen in the primary gastric non-B, non-Hodgkin lymphomas

Most primary gastric lymphomas are of B-cell origin. Fourteen cases of primary gastric non-B, non-Hodgkin lymphomas were studied to evaluate their clinicopathological and immunophenotypic findings. The cases were comprised of 11 men and three women, with a median age of 56.5 years. Most patients underwent surgery either with or without chemotherapy, exhibiting a 5 year survival rate of 57.5%. Morphologically, the neoplastic cells showed various histological features, such as anaplastic large cell lymphoma (ALCL) (n = 3), peripheral T-cell lymphoma, unspecified, large (n = 4), medium-sized (n = 2) and mixed cell (n = 5). Two cases displayed a non-B, non-T cell phenotype, whereas the remaining cases displayed a T-cell phenotype. Six cases were CD4+, while two were CD8+. The neoplastic cells were CD30+ in 10 cases. TIA-1 was positive in six cases. In one case, anaplastic large cell lymphoma kinase (ALK) was identified with immunostaining and chromosomal rearrangement of ALK was detected by fluorescence in situ hybridization (FISH). In conclusion, although the mechanism of CD30 expression is unknown, primary gastric non-B, non-Hodgkin lymphomas tend to express CD30. We consider that some of the cases in the present study may be derived from cytotoxic T cells, similar to systemic and cutaneous ALCL, the majority of which exhibit TIA-1.     

Primary cutaneous CD30 positive T-cell lymphoproliferative disorders with aberrant expression of PAX5: report of three cases

Accurate diagnosis of lymphoma includes the assessment of lineage-specific markers. Hematopoietic and lymphoid tissues express PAX5 exclusively in pro-B-cell to mature B-cell stages. However, some mature PAX5+ T-cell lymphomas have been reported. We report three cases of primary cutaneous CD30+ T-cell lymphoproliferative disorders (LPDs) with PAX5 expression: one cutaneous anaplastic large cell lymphoma (ALCL) and two cases of lymphomatoid papulosis (LyP). The three patients were 26 years old and female, 75 years old and female, and 65 years old and male. In all cases, Hodgkin's and Reed-Sternberg-like large lymphoid cells were present, positive for CD30, fascin, and PAX5, and negative for CD3, CD4, CD8, CD20, CD45RO, CD56, cytotoxic markers, and Epstein-Barr virus. The ALCL was accompanied by lymphadenopathy; the patient died of progressive disease 5 months after diagnosis. The LyP cases were localized in the skin with spontaneous regression. One case was diagnosed during pregnancy, transformed to ALCL, and ended in death 32 months after diagnosis despite multi-agent chemotherapy. This study is the first to address the clinical significance of PAX5+ primary cutaneous CD30+ T-cell LPDs. These cases were distinct regarding PAX5 expression and a relatively aggressive clinical course versus conventional primary cutaneous CD30+ T-cell LPDs.     

Monoclonal plasma cell infiltrates in the setting of cutaneous follicular helper T cell lymphoproliferative disorders

There is a growing recognition that some primary cutaneous T cell lymphomas of the skin exhibit a follicular helper T cell phenotype best exemplified by primary cutaneous CD4+ small/medium sized pleomorphic T cell lymphoma. The follicular helper T cells is an evolutionary function in a common TH1 cell under the influence of other cell types most notably monocyte derived dendritic cells but also plasma cells. In addition, the skin defines a characteristic organ site of involvement for angioimmunoblastic T-cell lymphoma (AITL); the first recognized form of follicular helper T cell lymphoma.One of the hallmarks of the follicular helper T cell lymphomas a significant degree of post germinal center B cell hyperplasia. We encountered 7 cases of primary cutaneous follicular helper T cell and four cases of AITL, in which the biopsies contained a light chain restricted plasma cell infiltrate in the skin. There were no features that suggested an atypical or more aggressive clinical course in association with the identification of this light chain restricted plasmacytic infiltrates except one case of AITL in whom a diffuse large cell B cell lymphoma subsequently developed.There was no association with Epstein–Barr virus (EBV) infection light chain restricted plasma cell infiltrate in any of the eleven cases. The basis of these infiltrates is likely a reciprocal functional one reflecting the role of follicular helper T cells in the induction of B cell hyperplasia and the role of plasma cells as a countercheck balance controlling the extent of follicular helper T cell hyperplasia. B cell clonality, plasma cell atypia and blastic B cell transformation can occur without implying a malignant transformation.     

Posttransplant primary cutaneous Ki-1 (CD30)+/CD56+ anaplastic large cell lymphoma

An anaplastic large cell lymphoma that was negative for Epstein-Barr virus and positive for Ki-1 (CD30) presented as a polypoid scalp mass in a 56-year-old man 16 years after renal transplantation. The lymphoma was of the CD4+ cytotoxic T-cell lineage, and the tumor cells also expressed CD56. Despite reduction in the dose of immunosuppression and localized radiotherapy, the tumor had rapidly progressed to involve the soft tissue of the right hand. Systemic chemotherapy induced complete regression of the soft tissue lesion. This case illustrates that posttransplant primary cutaneous CD30+ anaplastic large cell lymphomas may assume an aggressive clinical course but can still be controlled by systemic chemotherapy.     

Primary Cutaneous CD8-Positive Epidermotropic Cytotoxic T Cell Lymphomas : A Distinct Clinicopathological Entity with an Aggressive Clinical Behavior

Cutaneous T cell lymphomas (CTCL) generally have the phenotype of CD3+, CD4+, CD45RO+ memory T cells. CTCL expressing a CD8+ T cell phenotype are extremely rare and ill-defined. To elucidate whether these CD8+ CTCL represent a distinct disease entity, the clinical, histological, and immunophenotypical features of 17 CD8+ CTCL were reviewed. None of the 17 cases expressed markers characteristic of natural killer cells or gamma/delta T cells. Nine of 17 cases showed the characteristic clinical and histological features as well as clinical behavior of well defined types of CTCL, such as mycosis fungoides (2 cases), pagetoid reticulosis (2 cases), lymphomatoid papulosis (2 cases), and CD30+ large T cell lymphoma (2 cases), all of which usually express a CD4+ T cell phenotype, and 1 case of subcutaneous panniculitis-like T cell lymphoma. The other 8 cases formed a homogeneous group showing a distinctive set of clinicopathological and immunophenotypical features, not consistent with that of other well defined types of CTCL. Clinical characteristics included presentation with generalized patches, plaques, papulonodules, and tumors mimicking disseminated pagetoid reticulosis; metastatic spread to unusual sites, such as the lung, testis, central nervous system, and oral cavity, but not to the lymph nodes; and an aggressive course (median survival, 32 months). Histologically, these lymphomas were characterized by band-like infiltrates consisting of pleomorphic T cells or immunoblasts, showing a diffuse infiltration of an acanthotic epidermis with variable degrees of spongiosis, intraepidermal blistering, and necrosis. The neoplastic cells showed a high Ki-67 proliferation index and expression of CD3, CD8, CD7, CD45RA, betaF1, and TIA-1 markers, whereas CD2 and CD5 were frequently lost. Expression of TIA-1 pointed out that these lymphomas are derived from a cytotoxic T cell subset. The results of this and other studies reviewed herein suggest that these strongly epidermotropic primary cutaneous CD8+ cytotoxic T cell lymphomas represent a distinct type of CTCL with an aggressive clinical behavior.     

CD8+ lymphomatoid papulosis and its differential diagnosis

We describe 5 cases (4 males, 14-43 years old; 1 female, 61 years old) of primary cutaneous T-cell lymphoproliferative lesions expressing a CD8/granzyme/CD30-positive phenotype. Four cases were compatible with lymphomatoid papulosis (LyP) based on the clinical course, which was recurrent asymptomatic papular nodular lesions over years responding to methotrexate; granulomatous inflammation and lack of other inflammatory cell elements were characteristic. In 1 case, an initial erroneous diagnosis was made of aggressive epidermotropic CD8+ T-cell lymphoma. The fifth case in this series was first interpreted as representing primary cutaneous anaplastic large cell lymphoma but was later recategorized as primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma owing to the extent of extracutaneous dissemination, including testicular involvement and disease progression despite chemotherapeutic intervention. Although all cases of LyP showed sharp cytoplasmic membrane staining with perinuclear Golgi accentuation with CD30, the recategorized case of aggressive epidermotropic CD8 cytotoxic T-cell lymphoma manifested only a weak cytoplasmic staining pattern. CD8 LyP defines a distinctive entity with characteristic light microscopic and phenotypic findings and has a predilection for young males. CD30 expression can occur in other forms of CD8 lymphoproliferative disease unrelated to primary cutaneous anaplastic large cell lymphoma or LyP.     

Angiodestruction and tissue necrosis of skin-involving CD56+ NK/T-cell lymphoma are influenced by expression of cell adhesion molecules and cytotoxic granule and apoptosis-related proteins

We compared the expression of cell adhesion molecules (CAMs), cytotoxic granule proteins, and apoptosis-related proteins by immunohistology and in situ terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick end labeling (TUNEL) of 10 cases of cutaneous CD56+ NK/T cell lymphoma with and 6 cases without angiodestruction. Lymphoma cells in cases with angiodestruction frequently expressed CAMs CD2, CD11a, and CD49d and their ligands CD58, CD54, and CD106 and were positive for CD122 and cytotoxic granule proteins TIA1, perforin, and granzyme B. Lymphoma cells in cases without angiodestruction mostly were negative for CD2, CD58, CD54, CD106, and TIA1 and weakly positive for perforin and granzyme B. In the TUNEL method, mean apoptotic indices (AI) for cases with angiodestruction showed a higher percentage than those without angiodestruction. CD95L, CD95, apoptosis-induced cysteine protease CPP32, apoptosis-promoting protein Bax, and proliferating marker (MIB1) frequently were positive in the lymphoma cells of cases with angiodestruction, but there was no expression of apoptosis-inhibitor protein Bcl2. In most cases without angiodestruction, lymphoma cells were positive for CD95L and Bax and negative for CD95, CPP32, and MIB1. CAMs and the 3 cytotoxic granule proteins and an apoptosis pathway might be important factors in the paracrine and autocrine mechanisms of tissue necrosis in cutaneous CD56+ NK/T cell lymphoma.     

Small-cell variant of CD30+ -anaplastic large-cell lymphoma of the skin

Three cases of the so-called variant of primary cutaneous CD30+ anaplastic large cell lymphoma (ALCL) are presented. All patients were males aged 52, 59, and 78 years old; they had a solitary cutaneous tumor nodule. Their sites included the axilla, thigh, and shoulder. There was no extracutaneous involvement. Microscopically, the tumors were composed of small cells with irregular nuclei that were immunohistochemically positive for CD3, CD5, CD7, and CD30 and negative for B-cell markers; there was focal ALK-1 positivity in 1 case. Two cases had CD4+/CD8-phenotype, while the remaining one exhibited a CD4-/CD8+ immunoprofile. Fhedium to large CD30+ cells were rarely found scattered in the infiltrate. Monoclonal TCR gamma gene rearrangement was detected in 2 cases and rearrangement of IgH (lineage infidelity) was in one case. The tumors were surgically removed in all the patients. Two patients were alive and well 4 and 6 years after surgery, without evidence of cutaneous and extractaneous involvement (including the ALK+ patient). The third patient experienced several relapses of the skin tumor and developed axillary and inguinal lymph node involvement. Chemotherapy was performed and finally the patient underwent allogenic bone marrow transplantation; he died 3 years after the original diagnosis due to acute graft-versus-host disease and sepsis.     

T cell lymphoma co-expressing CD20

Haematological malignancies are currently classified by the WHO according to lineage, with stratification of non-Hodgkin lymphomas into B cell neoplasms, and T and NK cell neoplasms. Many laboratories routinely use CD20 and CD3 immunostains to identify B and T cell lymphomas respectively, with the use of additional immunomarkers where necessary.We report a case of an 84-year-old male with a peripheral lymphoma which stained positively with both CD3 and CD20. PCR of DNA extracted from paraffin embedded material was positive for clonal T cell receptor gene rearrangements but negative for clonal immunoglobulin gene rearrangement supporting a diagnosis of T cell lymphoma with aberrant CD20 positivity.This case is one of only a small number of reported cases of T cell lymphoma co-expressing CD20 and illustrates a potential pitfall in diagnosis. It emphasizes the need for 1) vigilant review of immunohistochemical stains to avoid misinterpretation and 2) the use of a wide immunohistochemical panel in lymphoma diagnosis with additional molecular studies where necessary.     

CD69 expression correlates with expression of other markers of Th1 T cell differentiation in peripheral T cell lymphomas

CD69, a marker of early T cell activation, is associated with Th1 T cell differentiation. Previously we found that peripheral T cell lymphomas could be subdivided based on the expression of markers of Th1 versus Th2 differentiation, including CXCR3, CD134/OX40, CCR4, and CD30. Here we report immunohistochemical staining for CD69 in frozen and paraffin sections of peripheral T cell lymphomas that exhibit immunoreactivity for markers of Th1 or Th2 differentiation. CD69 expression correlated with immunoreactivity for other Th1 differentiation markers in 18 of 19 frozen specimens of peripheral T cell lymphomas (P = 0.0005). In 10 of these cases in which paraffin-embedded tissue was available for study, CD69 immunohistochemical staining of paraffin sections correlated with frozen section expression. CD69 immunostaining was performed on paraffin sections from 53 additional cases of peripheral T cell lymphoma and correlated with immunoreactivity for other Th1 differentiation markers (P < 0.0001) and was associated with specific subtypes of peripheral T cell lymphoma, including angioimmunoblastic lymphoma, Lennert's lymphoma, and mycosis fungoides/Sezary syndrome, previously noted to express Th1 differentiation-associated markers. Anaplastic large cell lymphoma, both systemic and cutaneous, which typically exhibits immunoreactivity for markers of Th2 expression, was negative for CD69 immunostaining in 22 of 24 cases. CD69 immunostaining results support previous findings that a subset of T cell lymphomas exhibits immunophenotypic features of either Th1 or Th2 T cell differentiation. In addition, CD69 is a useful immunohistochemical marker for specific T cell lymphomas in frozen and paraffin-embedded tissue.     

Sinusoidal CD30-positive large B-cell lymphoma: a morphologic mimic of anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL) has been recognized recently as a distinct clinicopathologic entity, restricted to a subset of CD30-positive diffuse large cell lymphomas of T/null lineage. Some of the characteristic features of ALCL, such as CD30 antigen expression and the presence of large pleomorphic lymphoid cells infiltrating lymph node sinuses, can be found rarely in diffuse large B-cell lymphomas. We collected 11 such cases, and their clinical, morphologic, and immunophenotypic features are reviewed. The age of the patients ranged from 36 to 82 years (mean, 63.2 years) with a male to female ratio of 1:1.2. All neoplasms were nodal with a sinusoidal infiltrative pattern, although four neoplasms also had foci of confluent growth. Eight tumors were composed predominantly of large pleomorphic cells with occasional Reed-Sternberg-like cells. The other three tumors had a higher proportion of large monomorphic lymphoid cells. Necrosis and admixed granulocytes were other common features. Immunophenotypically, all cases were positive for CD30 and CD20 or CD79a. All eight cases examined for anaplastic lymphoma kinase-1 immunoreactivity were negative. In situ hybridization for Epstein-Barr virus RNA was performed in eight cases; two were positive. Excluding one consultation case with no available clinical follow-up data, six patients died of the disease within 3 years and one had disease relapse within 1 year. We conclude that an unusual variant of diffuse large B-cell lymphoma can closely mimic ALCL. However, these neoplasms can be distinguished from ALCL by virtue of their B-lineage and lack of anaplastic lymphoma kinase-1 expression. Evidence of Epstein-Barr virus infection can be found in a small subset of these neoplasms.     

A case of natural killer/T cell lymphoma of the subcutis resembling subcutaneous panniculitis-like T cell lymphoma

A case of nasal type natural killer (NK)/T cell lymphoma of the subcutis showing clinical and morphological features that resemble subcutaneous panniculitis-like T cell lymphoma (SPTCL) is presented. A 73-year-old man presented with swelling of the left arm and was diagnosed with panniculitis by a dermatologist. It was concluded from a skin biopsy specimen that the patient had non-Hodgkin's lymphoma of the large cell, NK/T cell type because the neoplastic cells showed polyclonal CD3 immunoreactivity. Treatment with interferon-gamma was initiated, but the patient died of disseminated intravascular coagulation and multiple organ failure 2 months after the initial symptoms appeared. However, involvement of additional organs by the lymphoma was not apparent clinically. An autopsy was not performed. A routinely stained section of the biopsy skin specimen revealed massive necrosis of the subcutaneous fat, karyorrhexis admixed with reactive histiocytes, and large atypical lymphoid cells. Immunoreactivity for polyclonal CD3 was present in the perinuclear region, but absent in the neoplastic cell membranes. CD56, CD45RO (UCHL-1), CD43 (MT1), CD45 (leukocyte common antigen), and the cytotoxic molecules perforin, granzyme B and TIA-1 were positive, but CD20 (L26), CD4, CD8, and betaF1 were negative. Epstein-Barr virus (EBV) mRNA was detected in the nuclei of neoplastic cells by in situ hybridization. Subcutaneous panniculitis-like T cell lymphoma is reported to be an EBV-negative, clonal T cell neoplasm. Although this case showed clinical and morphological features that resembled SPTCL, perinuclear polyclonal CD3 staining and membranous CD56 reactivity seen in neoplastic cells were suggestive of NK cells. Furthermore, the neoplastic cells were positive for EBV. This case is considered to be a NK/T cell lymphoma of the subcutis resembling SPTCL. It is believed that it is important to recognize such a tumor because patients may undergo a fulminant clinical course, despite the tumor being localized in the subcutaneous adipose tissue.     

Nasal CD56 positive small round cell tumors

CD56-positive nasal and nasal-type natural killer (NK)/T-cell lymphoma is now a well-defined disease entity. Rare cases of blastic NK-cell lymphoma positive for CD56 have been recently reported. However, CD56 expression is also identified in several types of non-hematopoietic small round cell tumors in which lymphoma is included as a differential consideration. Here, we present nine cases of CD56+ small round cell tumors of histological origin unrelated to nasal NK/T-cell lymphoma. Eight of the nine cases presented as solid tumors of the sinonasal region. Clinical, histological, ultrastructural, and immunohistochemical examination and gene analysis for T-cell receptor (TcR) and immunoglobulin heavy chain (IgH) genes and in situ hybridization (ISH) for Epstein-Barr virus (EBV) were performed. Two cases presented with features consistent with blastic NK-cell lymphoma or lymphoblastic lymphoma of NK-cell phenotype. These cases showed features of lymphoblastic lymphoma, phenotypes of sCD3-, cCD3+, CD45+, CD56+, TdT+, and human leukocyte antigen (HLA)-DR+, germline of IgH and TcR genes, and EBV negative reactivity. One case had myeloid/NK-precursor acute leukemia/lymphoma with a phenotype of CD13+, CD33+, CD34+, CD56+, and MPO-. Three cases were neurogenic, including one case of olfactory neuroblastoma and two of primitive neuroectodermal tumors (PNET). It was difficult to differentiate CD56+ PNET from blastic NK-cell lymphoma, especially when only paraffin-embedded sections were available. Myogenic markers, such as HHF35, alpha-sarcomeric actin, and desmin, were positive in three cases of rhabdomyosarcomas. Our findings suggest that as CD56 is used more routinely as a marker in immunohistochemical staining, the differential diagnosis of extranodal lymphohematological malignancies and small round cell tumors will become more complicated.     

Granzyme B-positive primary gastric T-cell lymphoma: gastric T-cell lymphoma with the possibility of extrathymic T cell origin

A case of primary gastric T-cell lymphoma, which was positive for granzyme B, is reported. The patient was a 47-year-old Japanese female who complained of a dull upper abdominal pain. Radiographic and endoscopic examinations revealed an ulcerative infiltrative lesion in her stomach. Following the confirmation of a high-grade malignant lymphoma, a distal gastrectomy with regional lymph nodal dissection was performed. The histology of the gastric lesion revealed a malignant lymphoma of the diffuse pleomorphic type without lymph nodal involvement. Immunohistochemistry revealed that the tumor cells were positive for LCA, CD3, TIA-1 and granzyme B, but were negative for CD4, CD8, CD56, CD30, L-26, EMA, TCR alpha/beta and TCR gamma/delta. Because the tumor cells showed T cell nature with cytotoxic activity proved by TIA-1 and granzyme B, and without evidence of further maturation of T cell, a malignant lymphoma originating from extrathymic-derived T cells was suggested.     

Hepatosplenic T cell lymphoma with no expression of cytotoxic molecules

Hepatosplenic T cell lymphoma is defined as an extranodal and systemic neoplasm derived from cytotoxic T cells. This report describes a postmortem case of T cell lymphoma that showed histological features of hepatosplenic T cell lymphoma but did not express cytotoxic molecules. The patient was a 57 year old man who presented with severe icterus and hepatosplenomegaly, followed by an aggressive clinical course. The liver and spleen were enlarged, weighing 2000 g and 360 g, respectively. Histologically, the liver, spleen, and bone marrow were entirely affected by lymphoma, comprising pleomorphic small and large cells, which displayed sinusoidal infiltration in the liver, diffuse infiltration in the splenic cord, and interstitial/diffuse infiltration with fibrosis in the bone marrow. Lymphoma cells showed positivity for CD3 epsilon, CD8, and CD45RO and clonal rearrangement of the TCRgamma gene by the polymerase chain reaction on paraffin wax embedded sections. However, they were negative for TIA-1 and granzyme B, in addition to betaF1, CD4, and CD56. Few neoplastic cells were stained for Epstein-Barr virus encoded mRNA 1. These findings indicate that this case might represent a variant of hepatosplenic T cell lymphoma despite the absence of cytotoxic molecules.     

Cutaneous intravascular natural killer/T cell lymphoma with peculiar immunophenotype

Intravascular lymphoma (IVL) is a rare entity. Most cases are a variant of extranodal diffuse large B cell lymphoma, and fewer than 10% of the published cases are of T cell origin. Only intravascular B cell lymphoma is recognized as a distinct entity in the most recent World Health Organization (WHO) classification of lymphoproliferative disorders. We describe a case of cutaneous natural killer (NK)/T IVL, with a cytotoxic immunophenotype and Epstein–Barr virus (EBV) positivity. However, our case was immunohistochemically negative not only for T cell receptor (TCR)‐βF1 and TCR‐γ (TCR‐silent), but also for CD56, making it the first triple‐negative NK/T IVL case to be described. We urge recognition of this NK/T cell lineage intravascular lymphoma due to its particular immunophenotypical profile and its unvarying relationship with EBV. Its occurrence should not be considered a coincidence, but rather a key aspect of the pathogenic background of this haematological neoplasm.     

Expression of killer cell inhibitory receptors is restricted to true NK cell lymphomas and a subset of intestinal enteropathy-type T cell lymphomas with a cytotoxic phenotype

BACKGROUND/AIMS: Killer inhibitory receptors (KIR) have a modulating effect on the cytotoxic functions of natural killer (NK) cells and T cells. Because lymphoma cells often have the same receptors as their non-neoplastic counterparts, this study investigated the expression of KIR on well defined groups of NK and T cell lymphomas, with and without a cytotoxic phenotype, from different sites of origin. METHODS: Nine CD56+/CD3- NK cell lymphomas, 29 CD3+/CD56- T cell lymphomas with a cytotoxic phenotype, and 19 T cell lymphomas without a cytotoxic phenotype were stained for KIR using monoclonal antibodies specific for CD94, CD158a, and CD158b. In addition, the expression of KIR was studied on normal lymphoid tissues. RESULTS: KIR expression was seen in five of nine true NK cell lymphomas including three of four nasal, one of four cutaneous, and one of one intestinal lymphoma nasal type. Double staining for CD56 and CD94 in normal lymphoid tissues revealed that KIR was predominantly expressed by CD56+ NK cells and sporadically on CD8+ T cells. Moreover, enteropathy-type T cell lymphomas with a cytotoxic phenotype showed KIR expression (three cases expressing CD94 and one case expressing CD158a). All nodal and extranodal nonintestinal T cell lymphomas with or without a cytotoxic phenotype lacked expression of KIR. CONCLUSIONS: These results show that KIR expression is restricted to CD56+/CD3- true NK cell lymphomas originating from the nose, gut, and skin, as well as in a subset of extranodal T cell lymphomas originating from the small intestine, which possessed a cytotoxic phenotype. Thus, the presence of KIR on NK/T cell lymphomas seems to mimic the distribution of KIR found on NK and T cells in normal lymphoid tissue.     

Immunoreactivity of B-cell markers (CD79a, L26) in rare cases of extranodal cytotoxic peripheral T- (NK/T-) cell lymphomas.

The monoclonal antibodies L26 (CD20) and CD79a are very useful reagents for the immunohistochemical assessment of B-cell lineage in lymphoproliferative disorders. Although very few CD20-positive peripheral T-cell lymphomas (PTL) have been reported, comprehensive analyses of CD79a reactivity in extranodal PTL and NK/T-cell lymphomas have not been performed previously. This study investigated CD79a (clone JCB117) and CD20 reactivity in 94 extranodal non-B-cell lymphomas (enteropathy-type intestinal T-cell lymphoma [n = 52], nasal NK/T-cell lymphoma [n = 11], and primary cutaneous PTL [n = 31]) and in 17 cases of nodal PTL, unspecified. In four cases (enteropathy-type intestinal T-cell lymphoma [n = 3] and nasal NK/T-cell lymphoma [n = 1]), the majority of tumor cells stained for CD79a (all CD20 negative) and one cutaneous PTL, unspecified, was CD20 positive (CD79a negative). Extensive immunophenotyping and polymerase chain reaction-based molecular analyses revealed that all five B-cell marker-positive extranodal lymphomas had a cytotoxic phenotype and did indeed represent monoclonal peripheral T-cell proliferations. To minimize the risk of misinterpretation of lymphoma cell lineage, especially in cases of extranodal, lymphoproliferative disease, we suggest the use of both CD79a and CD20 in combination with a panel of antibodies reactive to T cells, such as betaF1 and CD5, and to T cells and NK cells, such as CD3, CD2, CD56, and TIA-1.     

皮肤原发性CD30阳性间变性大细胞淋巴瘤

目的 探讨皮肤原发性CD30阳性间变性大细胞淋巴瘤（ALCL）的临床及组织病理学特征,为病理诊断和鉴别诊断提供依据。方法 采用组织病理学及免疫组织化学SP法的白细胞共同抗原、CD20、CD30、CD45RO、CD68、上皮膜抗原、细胞角蛋白和HMB45染色对9例皮肤原发性CD30阳性ALCL进行观察。结果 患者年龄31-84岁（平均58.2岁）,男女之比2：1,均以皮肤丘疹或皮下包块就诊。组织形态;瘤细胞体积大,呈多形性、圆形或椭圆形,胞质丰富。核大,核仁明显,核分型象多,常见R-S样细胞和多核巨细胞,CD30阳性,其中6例同时表达CD45RO,非T非B型3例表达,随访：2例因肿瘤转移而死亡,2例肿瘤复发,5例无复发,健在。结论 皮肤原发性CD30阳性ALCL是具有独特形态特点及预后较好的肿瘤,根组织病理特征及CD30阳性,可与其他恶性肿瘤鉴别。     

MUC1 (EMA) is preferentially expressed by ALK positive anaplastic large cell lymphoma, in the normally glycosylated or only partly hypoglycosylated form.

AIMS: To investigate whether MUC1 mucin, a high molecular weight transmembrane glycoprotein, also known as epithelial membrane antigen (EMA), differs in its expression and degree of glycosylation between anaplastic large cell lymphoma (ALCL) and classic Hodgkin's disease (HD), and whether MUC1 immunostaining can be used to differentiate between CD30 positive large cell lymphomas. METHODS/RESULTS: Using five different monoclonal antibodies (E29/anti-EMA, DF3, 139H2, VU-4H5, and SM3) that distinguish between various MUC1 glycoforms, high MUC1 expression (50-95% of tumour cells positive) was found in 13 of 17 anaplastic lymphoma kinase (ALK) positive systemic nodal ALCLs, and in one of 20 cases of classic HD. Scattered or focal staining (< 25% of tumour cells) was seen in two additional ALK positive systemic ALCLs, two additional classic HD cases, and in three of 20 cases of ALK negative systemic nodal ALCL. Primary cutaneous ALCL showed no staining with the anti-MUC1 antibodies. Antibodies detecting hypoglycosylated MUC1 were found to be absent in all lymphomas (SM3) or present in only six of 15 ALK positive ALCLs (VU-4H5). CONCLUSIONS: MUC1 is preferentially expressed by a subtype of systemic nodal ALCL, characterised by ALK expression, but is found in only a few cases of classic HD and ALK negative ALCL. Therefore, although MUC1 could be used in a panel of markers for CD30 positive lymphomas, it is probably not a valuable tool to differentiate between ALK negative CD30 positive large cell lymphomas. Finally, the degree of MUC1 glycosylation in lymphomas is relatively high, compared with the aberrant hypoglycosylation found in adenocarcinomas.