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Notes: Summary Skin biopsy specimens from normal skin and from 115 patients with benign dermatoses, pre- or pseudo-malignant disorders or malignant cutaneous lymphomas have been examined immunohistologically for expression of the Reed-Sternberg cell associated antigen CD30 detected by monoclonal antibodies Ki-1 and Ber-H2. The antibodies stained the atypical cells in lymphomatoid papulosis, a proportion of the neoplastic cells in some cases of mycosis fungoides and most of the neoplastic cells in six large cell anaplastic/pleomorphic non-Hodgkin's lymphomas. The lymphoid cells in all other specimens were Ki-1- and Ber-H2-negative. In all cases, expression of the Ki-1/Ber-H2 antigen was accompanied by expression of activation and proliferation associated markers (i. e., HLA-DR, IL-2 receptor, transferrin receptor and the Ki-67 nuclear antigen). These data indicate the value of antibodies Ki-1 and Ber-H2 in distinguishing between lymphomatoid papulosis and other types of pre- or pseudo-malignant disorders and support the view that lymphomatoid papulosis, Hodgkin's disease and some types of non-Hodgkin's lymphoma constitute a spectrum of related disorders, originated from activated lymphoid cells.

Notes: Abstract Cushing syndrome due to primary adrenocortical nodular dysplasia was diagnosed in two patients, aged 3 years 9 months and 9.5 years. Subsequently, adrenalectomy was performed and followed by steroid replacement. In both cases, the adrenals were normal or only slightly enlarged and showed adrenocortical nodular dysplasia histologically. Small lymphocytic infiltrates consisting of T-cells and class II MHC positive macrophages were present in adrenal specimens of both the patients. Samples of protein A sepharose purified serum immunoglobulins from both children stimulated adrenocortical DNA synthesis and cortisol production in cultured guinea-pig adrenal segments in vitro in a dose dependent fashion. Adrenal stimulating immunoglobulins were also demonstrated in serum specimens of both patients' mothers. However, none of them had overt signs of adrenal disease. Our data support the view that autoimmune mechanisms may be involved in primary adrenocortical nodular dysplasia.

Notes: CD 3 antigen expression was studied in a series of 98 T-cell lymphomas, using polyclonal antibodies which recognize this molecule in routinely processed, paraffin-embedded, tissue. We identified 40 cases in which CD3 was present on only a proportion of the neoplastic cells. This phenomenon of heterogeneous CD3 expression was commonest in pleomorphic T-cell lymphomas (22/42 cases) and in CD30 (Ki-1)-positive lymphomas (5/11 cases), and was less frequently observed in mycosis fungoides (4/18 cases) and not seen in T-cell lymphoblastic lymphoma (0/9 cases). CD3 expression was often related to cell morphology, with CD3 antigen being present on the smaller neoplastic cells but absent from the larger ones. The diagnostic significance of these observations is that, on occasion, it may be possible to diagnose a lymphoma as being of T-cell origin in paraffin sections by demonstrating a minor subpopulation of CD3-positive neoplastic cells.

Notes: The reactivity of a monoclonal anti-neutrophil elastase antibody (NP57) with routinely processed biopsy samples from various acute leukaemias has been examined and compared with that of chloroacetate esterase and CD15 (hapten X), two other myeloid cell-associated markers detectable in paraffin sections. No staining was seen with these markers in 14 cases of acute lymphoblastic leukaemia. In contrast the neoplastic cells in 27 of 37 acute myeloid leukaemias were NP57 positive. Twenty of these were also positive for chloroacetate esterase, whereas CD15 was expressed in only six cases. These results indicate that detection of elastase with monoclonal NP57 forms a useful supplement to traditional methods for the histopathological diagnosis of acute myeloid leukaemias.

Notes: Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with `malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer–Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms.

Notes: Paraffin-wax embedded specimens from 30 cases of colonic adenocarcinoma were investigated for immunoreactivity for the receptor of urokinase-type plasminogen activator (uPAR). In all cases there was a strong signal, predominantly at the invasive foci. The positive cells were mainly tumour-infiltrating macrophages but neutrophils and eosinophils were also strongly stained. The neoplastic cells were positive in 19 of the samples with staining of occasional or a moderate number of cells. In uninvolved, normal-appearing mucosa adjacent to the malignant infiltrates, immunostaining of both macrophages and neutrophils was seen, but the labelling was less intense than that seen in the malignant lesions. Weak to moderate staining of normal intestinal epithelium was also seen at the luminal surface. Comparison between immunoreactivity and in situ hybridization showed a similar distribution of protein and mRNA with two exceptions: first, neutrophils (strongly immunoreactive for uPAR) were negative or only weakly positive for uPAR mRNA; and second, many cancer cells at invasive foci showed prominent hybridization signals but no detectable uPAR immunoreactivity. Together with previous findings of urokinase plasminogen activator (uPA) protein and mRNA being expressed in tumour-infiltrating fibroblast-Iike cells at the invasive foci, these results support the view that the uPA pathway of plasminogen activation is involved in tissue degradation in colon cancer. The results also extend and consolidate an emerging picture of non-neoplastic tumour stromal cells producing molecules involved in the generation and regulation of extracellular proteolysis in cancer.

Notes: Haematoxylin and eosin, and Giemsa stained sections from 100 peripheral T-cell lymphomas were examined blind on two occasions by four experienced haematopathologists in order to evaluate the inter- and intra-observer reproducibility of the updated Kiel classification for these malignancies. In all cases, the T-cell phenotype had been established previously in frozen section using a panel of monoclonal antibodies. Analysis by kappa statistics showed poor reproducibility, both overall and for most subtypes, with the exception of large cell anaplastic lymphoma. The distinction between low- and high-grade lymphomas was also unsatisfactory. These results indicate the need for improved precision in the definition of histological categories of peripheral T-cell lymphoma. The reproducibility of the updated Kiel classification for peripheral T-cell lymphomas in its present form is inadequate.

Notes: A new classification of lymphoid neoplasms, mostly based on existing terminology, is proposed by the International Lymphoma Study Group. The proposed classification was reached through a consensus of the members, despite their diverse backgrounds, and consists of a listing of currently recognized clinicopathological entities. These tumours are divided into three major categories: B-cell neoplasms, T-cell and postulated natural killer cell neoplasms, and Hodgkin's disease. The characterization of each entity is based on a synthesis of all available information. This concept departs from a purely morphological approach to lymphoma classification, which is considered to be inadequate, because many biologically distinctive lymphoma types can exhibit a broad and overlapping morphological spectrum. Some entities are provisional, pending further data to confirm that their recognition is reproducible. The salient clinicopathological features of each entity are summarized in this review.

Notes: The presence of intercellular adhesion molecule-1 (ICAM-1) on keratinocytes of psoriatic skin lesions before and during 8-methoxapsoralen and UVA light (PUVA) treatment was studied. ICAM-1 was expressed on the keratinocytes in biopsies of the skin lesions of five patients with psoriasis. The patients who responded to PUVA treatment had a concurrent reduction of ICAM-1 expression on the keratinocytes with a reduction of the number of cells in the mononuclear cellular infiltrate and a lessening of the severity of the disease. Patients who went into remission during therapy and then relapsed showed an increase in ICAM-1 expression on keratinocytes with an increase in the number of cells in the mononuclear cell infiltrate and an increase in the severity of the disease. HLA-DR expression on keratinocytes was variable during treatment and showed no strong correlation with disease severity.

Notes: Examination of biopsies from 62 patients with, or suspected of having cutaneous T-cell lymphoma (CTCL) revealed 24 cases in which the neoplastic cells expressed aberrant or suppressor T-cell phenotypes. The clinical records of these patients were reviewed in an attempt to establish whether recognition of these phenotypes has any clinical implications. Twelve patients had mycosis fungoides (MF) with plaques (n=4) or tumours (n=8), four had Sézary syndrome, and eight had large-cell lymphomas of pleomorphic (n=6) or anaplastic subtype (n=2). Most of the large-cell lymphomas behaved aggressively, as might have been expected from their cytological appearance. Aggressive courses were also seen in Sézary syndrome, and in tumour lesions of MF, whereas the behaviour in cases of plaque lesions was indolent. Again, this might have been anticipated from the clinical staging and routine histological examination. It is suggested that the expression of aberrant or suppressor T-cell phenotypes in CTCL is not of independent prognostic significance, but that the stage and histology are more important. This issue is an important topic for a prospective analysis.