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.

Síndrome hemofagocítico / Haemophogocytic syndrome

El sindrome hemofagocítico es una proliferación reactiva de histiocitos benignos, asociados a fagocitosis de elementos hemopoyéticos y pancitopenia periferica. Entre los factores desencadenantes se ha encontrado una infección viral activa en el 80 por ciento de los casos. En su patogenia estaría involucrada como hecho basico, la activación descontrolada de celulas T, con la consecuente cascada patológica que conduciria a la proliferación reactiva de monocitos e histiocitos y la hemofagocitosis secundaria. Los hallazgos clínicos mas observados son hepatoesplenomegalia, linfoadenopatías y fiebre. Se analiza una paciente internada en la Sala XIX del Pabellón DïAmelio del HIGA Gral. San Martín de La Plata, que se presentó con esta enfermedad, manifestada por pancitopenia y compromiso multiorgánico y desencadenada por el virus B de la hepatitis. Se expone el diagnóstico y tratamiento.