Histopathological and immunophenotypical characterization of canine multicentric lymphoma in Brazil: a study of 203 cases / Caracterização histopatológica e imunofenotípica do linfoma multicêntrico canino no Brasil: um estudo de 203 casos

The immunophenotype is regarded as an independent prognostic factor in high-grade lymphomas, seeing that lymphomas of T-cell origin are associated with shorter survival time. Although a number of studies have evaluated the immunophenotypical profile of lymphoma in the USA and Europe, Brazilian research on the matter remains scarce. Exact characterization of the histopathological type is crucial to establish proper treatment and prognosis. This study evaluated the database of immunohistochemistry laboratories that perform immunophenotyping of canine lymphoma in Brazil. A total of 203 cases of multicentric lymphoma were classified according to the WHO classification. Immunophenotyping was able to identify 71.4% lymphomas of B-cell line, 27.1% of T-cell line and 1.5% of non-B cells and non-T cell lines. Diffuse large B-cell lymphoma was the most common with 59.1% of the cases. Among T-cell lymphomas, lymphoblastic was the most common (11.33% of the cases). Even though canine lymphomas tend to be high-grade, indolent lymphomas comprised 11.82% of the cases and T-zone lymphoma was the most prevalent (8.86%). The immunophenotype of multicentric lymphoma in Brazil is similar to those in other parts of the world, which suggests similar etiologic factors to the development of this disease.(AU)

O imunofenótipo é considerado um fator prognóstico independente em linfomas de alto grau, visto que os linfomas de origem de células T estão associados a menor tempo de sobrevida. Apesar de vários estudos terem avaliado o perfil imunofenotípico do linfoma nos EUA e na Europa, a pesquisa brasileira sobre o assunto ainda é escassa. A caracterização exata do tipo histopatológico é crucial para estabelecer o tratamento e o prognóstico adequados. Este estudo avaliou a base de dados de laboratórios de imuno-histoquímica que realizam imunofenotipagem do linfoma canino no Brasil. Um total de 203 casos de linfoma multicêntrico foi classificado de acordo com a classificação da OMS. A imunofenotipagem foi capaz de identificar 71,4% dos linfomas da linhagem de células B, 27,1% da linhagem de células T e 1,5% das linhagens de células não B e não T. O linfoma difuso de grandes células B foi o mais comum em 59,1% dos casos. Entre os linfomas de células T, o linfoblástico foi o mais comum (11, 33% dos casos). Embora os linfomas caninos tendam a ser de alto grau, os linfomas indolentes representaram 11,82% dos casos e o linfoma da zona T foi o mais prevalente (8,86%). O imunofenótipo do linfoma multicêntrico no Brasil é semelhante ao de outras partes do mundo, o que sugere fatores etiológicos semelhantes ao desenvolvimento dessa doença.(AU)

T-Cell Lymphomas in South America and Europe

Peripheral T-cell lymphomas are a group of rare neoplasms originating from clonal proliferation of mature post-thymic lymphocytes with different entities having specific biological characteristics and clinical features. As natural killer cells are closely related to T-cells, natural killer-cell lymphomas are also part of the group. The current World Health Organization classification recognizes four categories of T/natural killer-cell lymphomas with respect to their presentation: disseminated (leukemic), nodal, extranodal and cutaneous. Geographic variations in the distribution of these diseases are well documented: nodal subtypes are more frequent in Europe and North America, while extranodal forms, including natural killer-cell lymphomas, occur almost exclusively in Asia and South America. On the whole, T-cell lymphomas are more common in Asia than in western countries, usually affect adults, with a higher tendency in men, and, excluding a few subtypes, usually have an aggressive course and poor prognosis. Apart from anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, that have a good outcome, other nodal and extranodal forms have a 5-year overall survival of about 30 percent. According to the principal prognostic indexes, the majority of patients are allocated to the unfavorable subset. In the past, the rarity of these diseases prevented progress in the understanding of their biology and improvements in the efficaciousness of therapy. Recently, international projects devoted to these diseases created networks promoting investigations on T-cell lymphomas. These projects are the basis of forthcoming cooperative, large scale trials to detail biologic characteristics of each sub-entity and to possibly individuate targets for new therapies.

Papulosis linfomatoide / Lymphomatoid papulosis

La papulosis linfomatoide (PL) es considerada en la actualidad una forma indolente de linfoma cutáneo CD30+. Su presentación es más frecuente entre la 4º y 5º décadas de la vida, con un discreto predominio en el sexo masculino (1,5/1). Su mecanismo etiopatogénico es complejo y se ha vinculado principalmente con factores genéticos e inmunitarios. Aunque exhibe características clínicas de benignidad, se manifiesta histológicamente con rasgos de malignidad. Las técnicas inmunohistoquímicas resultan de utilidad a los fines diagnósticos y recientemente han permitido la identificación de un nuevo tipo de PL que remeda un linfoma cutáneo primario agresivo a células T epidermotrópico CD8+ (propuesto como PL tipo D). Puede hallarse asociada a otros trastornos linfoproliferativos y a entidades inflamatorias con perfil de citocinas Th2, entre otros. El diagnóstico diferencial con otros linfomas cutáneos, y especialmente con los casos que presentan el antígeno CD30, puede a veces resultar muy dificultoso. Si bien la PL tiene un curso clínico benigno, quienes la padecen tienen un mayor riesgo de desarrollar una segunda neoplasia. Las opciones terapéuticas disponibles son múltiples; sin embargo, ninguna de ellas ha resultado hasta ahora completamente eficaz.

Incidence and Histologic Patterns of Bone Marrow Involvement of Malignant Lymphoma Based on the World Health Organization Classification: A Single Institution Study / 대한진단검사의학회지

BACKGROUND: Working Formulation and Revised European American Classification of Lymphoid Neoplasms (REAL) have mainly been used in the studies for bone marrow involvement of malignant lymphoma in Korea. We investigated the incidence and histologic patterns of malignant lymphoma according to the WHO classification. METHODS: This study included 507 cases of malignant lymphoma that were requested for bone marrow study for the staging during the period January 1999-December 2005 in Korea Cancer Center Hospital. Medical records, peripheral blood smears, bone marrow aspiration smears, biopsy sections, and histopathologic findings were analyzed retrospectively. RESULTS: Of the 507 cases of malignant lymphoma, 473 (93.3%) were non-Hodgkin lymphoma (NHL) and 34 (6.7%) were Hodgkin lymphoma (HL). The overall incidence of bone marrow involvement by NHL and HL was 12.5% (59/473) and 11.8% (4/34), respectively. Among NHL cases, the incidence of bone marrow involvement by B-cell and T-cell neoplasms was 11.4% (43/377) and 16.7% (16/96), respectively. Although the incidences of bone marrow involvement by several B-cell neoplasms were more than 30%, diffuse large B cell lymphoma showed a relatively low incidence of bone marrow involvement (4.6%). Of bone marrow involvement patterns, diffuse infiltration pattern was the most common (40.0%). Peripheral blood involvement by lymphoma was observed in 35.6% of cases with bone marrow involvement. CONCLUSIONS: We used WHO classification in the study for the bone marrow involvement of malignant lymphoma, and this single-institution study should give a useful, up-to-date histopathologic information.