RESUMO
Progressive transformation of germinal center (PTGC) is a pattern of lymph node reactive hyperplasia. It can also be the predominant pattern in a hyperplastic lymph node known as florid PTGC. It is characterized histologically by the expansion of the mantle zone lymphocytes into both the adjacent sinusoids and germinal centers. The lymphocytes destroying the germinal centers are predominantly B cells, with a minor population of T cells. Morphologically, it can be confused with nodular lymphocyte-predominant Hodgkin disease (NLPHD) because of its nodular pattern and because of the presence of large cells that can be incorrectly identified as lymphocytic and histiocytic cells. A relationship between PTGC and NLPHD remains unclear, and many authors have suggested that PTGC can represent a precursor lesion of NLPHD. Here we report the first karyotype obtained in PTGC, in a 12-year-old boy. It shows a t(3;22)(q27;q11) translocation, probably involving the BCL6 gene. This translocation has previously been described in diffuse large B-cell lymphomas and in NLPHD with BCL6 rearrangement. This finding offers an insight into a possible tumorigenic pathway from PTGC to NLPHD. Further studies will be required to confirm this hypothesis.
Assuntos
Transformação Celular Neoplásica/patologia , Cromossomos Humanos Par 22 , Cromossomos Humanos Par 3 , Centro Germinativo/patologia , Linfoma de Células B/genética , Linfoma de Células B/patologia , Translocação Genética/genética , Hiperplasia do Linfonodo Gigante/genética , Hiperplasia do Linfonodo Gigante/patologia , Criança , Bandeamento Cromossômico , Humanos , Técnicas Imunoenzimáticas , Cariotipagem , MasculinoAssuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteínas de Ligação a DNA/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas de Fusão Oncogênica/genética , Fatores de Transcrição/genética , Translocação Genética , Bandeamento Cromossômico , Cromossomos Humanos Par 22/genética , Cromossomos Humanos Par 9/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Cariotipagem Espectral , Fatores de Transcrição/metabolismoRESUMO
A case of acute myelocytic leukemia (AML) M5 subtype (French-American-British classification), in a 13-year-old girl showed the abnormal karyotype 46,XX,t(11;17)(q23;q21) in all bone marrow cells analyzed. Rearrangements involving 11q23 are frequent in cases of AML M5 and often involve the MLL gene. Nevertheless, t(11;17)(q23;q21) is very rare in this type of leukemia. In acute promyelocytic leukemia, the RARalpha gene, located at 17q21, is involved in almost all cases. Fluorescence in situ hybridization studies revealed a deletion of the C-terminal part of the MLL gene and a translocation of the RARalpha gene on the derivative chromosome 11, proximal to the remaining part of the MLL gene. However, hybridization with the LSI RARA dual color break-apart rearrangement probe showed that the RARalpha gene was not rearranged in this translocation. This is the first study reporting a t(11;17)(q23;q21) with a deletion distal to MLL gene exon 6 in a case of AML M5. Furthermore, this is the second study that strongly suggests the implication of a gene proximal and close to the RARalpha locus in a case of AML M5. According to these results, the discovery of new fusion partner genes of MLL and the precise characterization of t(11;17) will be important for the understanding of neoplastic cell differentiation in AML M5.
