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Publication
Linfoma granular de células grandes em felinos
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Advisor(s)
Abstract(s)
O linfoma granular de células grandes felino (LGL do inglês large granular lymphocytes) é
classificado pela Organização Mundial de Saúde (OMS) como um subtipo de linfoma de células
T associado a enteropatia tipo I, em que as células apresentam grânulos citoplasmáticos
azurófilos, visíveis no exame citológico. Na maioria dos casos, o linfoma LGL desenvolve-se na
mucosa do intestino delgado, principalmente no jejuno, com envolvimento posterior de outros
órgãos e possível leucemia LGL secundária. Estes gatos apresentam um quadro clínico
gastrointestinal (GI), com aumento segmentar do intestino, que com o tempo evolui para uma
massa tumoral facilmente detetável durante o exame clínico. No entanto, existem casos
reportados sem envolvimento GI. É um subtipo de linfoma raro, que apresenta um
comportamento biológico muito agressivo na maioria dos casos, e não é comumente descrito na
literatura. Todos os estudos publicados mostram tempos de sobrevida mais baixos em
comparação com outros subtipos de linfoma, com fraca resposta à quimioterapia. No entanto,
alguns casos esporádicos, apresentam um melhor prognóstico.
Fenotipicamente, tanto os LGL neoplásicos como os linfócitos intra-epiteliais (IEL do inglês
Intra-epithelial lympchocytes) expressam CD103 (αEβ7) e CD8αα, o que sugere que estes
linfomas possam ter origem nestas células. Para além disso, o linfoma LGL felino pode ter um
processo inflamatório na sua génese, evoluindo para um processo crónico, ocorrendo uma
estimulação antigénica prolongada que leva a uma transformação clonal das células T intraepiteliais
intestinais. Contudo, a origem numa inflamação crónica do intestino, permanece por
ser confirmada.
Assim, foi objetivo desta revisão descrever este linfoma de forma aprofundada, discutindo a
sua possível origem e fatores de prognóstico. Esta revisão visa também contribuir para
impulsionar estudos futuros que permitam incrementar o conhecimento sobre esta doença.
Large granular lymphoma (LGL large granular lymphocytes) is classified by the World Health Organization (WHO) as a subtype of T-cell lymphoma associated with enteropathy type I, in which cells have azurophilic cytoplasmic granules visible on cytological examination. In most cases, LGL lymphoma develops in the mucosa of the small intestine, mainly in the jejunum, with posterior involvement of other organs and possible secondary LGL leukemia. These cats present a clinical signs of gastrointestinal (GI) disease, with segmental increase of the intestine, which over time evolves to an tumor mass easily detectable during clinical examination. However, there are cases reported without GI involvement. Feline LGL lymphoma is a rare lymphoma that exhibits a very aggressive biological behavior in mos cases, and is not commonly described in the literature. All published studies show lower survival rates compared to other lymphoma subtypes, having a very poor response to chemotherapy. However, sporadic cases present a better prognosis. Phenotypically both neoplasic LGL and intraepithelial lymphocytes (IEL Intra-epithelial lymphocytes) express CD103 (αEβ7) and CD8αα, suggesting that these lymphomas may arise from these cells. In addition, this subtype of lymphoma can develop from an inflammatory process that evolves into a chronic stage, in which the prolonged antigenic stimulation stimulates the intraepithelial T cells to go trought a clonal transformation. However, the origin of the chronic inflammation of the intestine remains unknown. Thus, the objective of this review was to describe this lymphoma in depth, discussing its possible origin and prognostic factors. This review also aims to contribute to future research to increase knowledge about this disease.
Large granular lymphoma (LGL large granular lymphocytes) is classified by the World Health Organization (WHO) as a subtype of T-cell lymphoma associated with enteropathy type I, in which cells have azurophilic cytoplasmic granules visible on cytological examination. In most cases, LGL lymphoma develops in the mucosa of the small intestine, mainly in the jejunum, with posterior involvement of other organs and possible secondary LGL leukemia. These cats present a clinical signs of gastrointestinal (GI) disease, with segmental increase of the intestine, which over time evolves to an tumor mass easily detectable during clinical examination. However, there are cases reported without GI involvement. Feline LGL lymphoma is a rare lymphoma that exhibits a very aggressive biological behavior in mos cases, and is not commonly described in the literature. All published studies show lower survival rates compared to other lymphoma subtypes, having a very poor response to chemotherapy. However, sporadic cases present a better prognosis. Phenotypically both neoplasic LGL and intraepithelial lymphocytes (IEL Intra-epithelial lymphocytes) express CD103 (αEβ7) and CD8αα, suggesting that these lymphomas may arise from these cells. In addition, this subtype of lymphoma can develop from an inflammatory process that evolves into a chronic stage, in which the prolonged antigenic stimulation stimulates the intraepithelial T cells to go trought a clonal transformation. However, the origin of the chronic inflammation of the intestine remains unknown. Thus, the objective of this review was to describe this lymphoma in depth, discussing its possible origin and prognostic factors. This review also aims to contribute to future research to increase knowledge about this disease.
Description
Keywords
Grânulos azurófilos Linfoma felino Linfócitos granulares grandes Linfócitos intra-epiteliais Linfoma de células T associada a enteropatia Azurophilic granules Feline lymphoma Large granular lymphocytes Intraepithelial lymphocytes Enteropathy-associated T-cell lymphoma