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Query: UMLS:C0268596 (EMA)
 2,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microvillous non-hodgkin lymphomas are large cell malignant lymphomas with a sinus growth pattern and the presence of cytoplasmic processes detected by electron microscopy. Microvillous non-hodgkin lymphomas appear to be of B cell lineage. Neoplasms considered in the differential diagnosis include anaplastic large cell Ki-1 lymphomas, malignant histiocytosis and metastatic carcinoma or malignant melanoma. A panel of markers are usually sufficient to recognize all of these neoplasms except microvillous lymphomas. We report a case of microvillous non-hodgkin lymphoma characterized by a histologic pattern mimicking those of anaplastic large cell Ki-1 lymphoma. However, immunohistochemistry study failed to demonstrate presence of activation antigen such as Ki-1, EMA, interleukin 2 receptor. Ultrastructural study showed that neoplastic cells exhibited filliform cytoplasmic processes. This report raise the possibility of an overlap between microvillous non-hodgkin lymphomas and anaplastic large cell Ki-1 lymphomas of B-cell lineage. It must be emphasized that, initially, these two kinds of lymphomas were defined with different morphologic technologies.
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PMID:[Is it possible to individualize microvillous large-cell lymphoma among sinusoid lymphomas?]. 831 63

We describe a patient with leukopenic T-cell chronic lymphocytic leukemia/prolymphocytic leukemia (T-CLL/PLL), according to the Revised European-American Classification of Lymphoid Neoplasms. This patient simultaneously developed classic Hodgkin's disease (HD), a combination previously unreported. The leukemic cells were small and mature, did not have cytoplasmic granulation, and appeared similar to B-cell chronic lymphocytic leukemia. Immunophenotyping of the bone marrow-infiltrating cells revealed a postthymic suppressor/cytotoxic phenotype of CD2+, CD3+, CD4, CD5+, CD8+, CD25-, TCR-alpha beta. A lymph node biopsy showed the histological features of HD (mixed cellularity) with infiltrating CD8+ lymphocytes, and immunohistochemical examination revealed the following phenotype of Reed-Sternberg cells: LeuM1/CD15+, BerH2/CD30+, L26/PanB-, UCHL-1/CD45RO-, cyCD3-, CD4, CD8-, CD20-, CD79a-, EMA-, EBER-1+, LMP-1+. Southern blot analysis of the bone marrow and lymph node revealed the same rearrangement of bands of T-cell-receptor genes. Although the HD was treated with chemotherapy that resulted in complete remission, the T-PLL/CLL took an indolent course. This case may suggest the existence of a subtype of T-CLL/PLL with leukopenia and an indolent clinical course. Both diseases were believed to be independent and not a transformation of one to the other.
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PMID:Concurrent Hodgkin's disease (mixed cellularity type) and T-cell chronic lymphocytic leukemia/prolymphocytic leukemia. 1137 37

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.
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PMID:Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases. 1212 Dec 33

Neoplasms of unknown origin present a difficult diagnostic dilemma, particularly if they are very poorly differentiated. Adenocarcinomas, squamous cell carcinomas, melanomas, lymphomas, and sarcomas can all be very difficult to diagnose if the light microscopic cytomorphology is sufficiently undifferentiated. Electron microscopy (EM) can either demonstrate differentiation or narrow the range of differential diagnoses. The authors report the case of a 64-year-old male who has been HIV positive for several years and was found to have expansile lytic lesions in several ribs and a thumb fracture associated with a soft tissue mass which was biopsied. The tumor was composed of very pleomorphic malignant cells without specific differentiation. The malignant cells stained positive for pancytokeratin (AE 1/3), EMA, CEA, CK20, and CK7. Rare cells had mucicarmine-positive intracytoplasmic droplets. They were negative for S-100, calretinin, CD45, MART-1, and vimentin. EM revealed intracytoplasmic lumina with long microvilli and many well-formed desmosomal junctions. The diagnosis was initially very broad. Immunohistochemistry narrowed the diagnosis to carcinoma, but EM alone was able to narrow the diagnosis to poorly differentiated adenocarcinoma. In a neoplasm of unknown origin, EM can either narrow the differential significantly or, in the case of limited material, provide information that otherwise may not be attainable.
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PMID:Desmosomes and microvilli mean a lot: diagnosis of neoplasms of unknown origin using electron microscopy. 1277 6