RESUMO
Introduction Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease, the spectrum of which is increasing with time. The 2016 World Health Organization (WHO) update on hematopoietic tumors recognized a prognostic subgroup of DLBCL called double-expressor DLBCL. Double-expressor DLBCL is defined by the co-expression of c-MYC and BCL-2 by using immunohistochemical (IHC) studies. To our knowledge, very few studies have looked into the pathological features of this newly defined prognostic category of DLBCL; therefore, in this study we evaluated the frequency of the double-expressor phenotype of DLBCL and its association with other clinicopathological parameters. Methods We conducted a retrospective observational study in the Department of Histopathology, Liaquat National Hospital and Medical College, from November 2017 till December 2020. Pathological and clinical records were retrieved from departmental archives. All cases diagnosed as DLBCL were included in the study. More than 40% c-MYC expression in the presence of more than 50% BCL-2 expression was defined as double-expressor DLBCL. Results The mean age of the patients was 52.1±16.9 years. The mean Ki67 index was 73.0±17.0%. A total of 48.6% cases were of germinal center B-cell-like (GCB) subtype, and 59.6% cases were nodal. Double-expressor phenotype was noted in 35.8% of DLBCL cases. A significant association of double-expressor phenotype was noted with age, gender, Ki67 index and subtype of DLBCL. Double-expressor DLBCL had a higher mean age than non-double-expressor DLBCL. Similarly, double-expressor DLBCL had a higher Ki67 index. Moreover, double-expressor phenotype was associated with non-GCB subtype DLBCL. Conclusion We found a high proportion of double-expressor phenotype DLBCL in our population. Moreover, double-expressor phenotype DLBCL was associated with female gender, higher age, higher Ki67 and non-GCB subtype. The association of double-expressor DLBCL with a high Ki67 index and non-GCB subtype confers a poor prognostic significance of this variant of DLBCL, requiring more aggressive therapy.
RESUMO
Introduction Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma and is the most common type of non-Hodgkin's lymphoma (NHL) worldwide. The World Health Organization (WHO) classification of hematopoietic tumors has recognized three morphological variants of DLBCL: centroblastic, immunoblastic, and anaplastic. Some studies have shown that the anaplastic variant of DLBCL is associated with aggressive clinicopathological features. Anaplastic DLBCL is rare, and the clinicopathological characteristics of this subtype of DLBCL are not widely studied in our population. Therefore, in this study, we evaluated the frequency of the anaplastic variant of DLBCL and its association with other clinicopathological parameters. Methods A retrospective study was conducted in the Department of Histopathology at the Liaquat National Hospital and Medical College over a period of six years, from January 2015 to December 2020. All cases diagnosed as DLBCL based on morphology and immunohistochemical (IHC) profile were included in the study. The diagnosis of anaplastic DLBCL was rendered based on morphology (large bizarre pleomorphic cells in a cohesive or sheet-like growth pattern), combined with CD30 IHC expression. Results The mean age of the patients was 52.90 ±16.42 years, and the mean Ki67 index was 73.18 ±16.52%. Of the 220 cases of DLBCL, 47.3% cases were germinal center B-cell (GCB) subtype, and 59.1% cases were nodal. BCL-2, BCL-6, MUM1, c-MYC, and CD10 positivity were noted in 60%, 45.5%, 40.9%, 44.1, and 38.6% cases, respectively. Only 14 cases (6.4%) were recognized as anaplastic variants of DLBCL according to the previously defined criterion. The only significant association of anaplastic-variant DLBCL was noted with a lack of BCL-2 expression. No significant association of anaplastic-variant DLBCL was noted with age, gender, Ki67 index, DLBCL subtype, or any other IHC marker expression. Conclusion We found a low frequency of the anaplastic variant of DLBCL in our study. No significant association of this DLBCL variant was noted with any of the clinicopathological parameters, except for the lack of BCL-2 expression. Alternatively, from a pathological perspective, it is important to recognize this variant of DLBCL as it often mimics other CD30-positive lymphoma and undifferentiated carcinoma.
RESUMO
Introduction Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma. The 2016 World Health Organization (WHO) update on hematopoietic tumors suggested that all DLBCL cases should be subtyped into germinal and non-germinal center phenotypes. Ki67 immunohistochemistry is a maker of cell proliferation and thus is used as a prognostic and predictive marker in various tumors of human body. Only a few studies evaluated the proliferative index of DLBCL subtypes in our population. Therefore, in this study, we evaluated the frequency of subtypes of DLBCL in our population and K67 index in each subtype. Methods A retrospective observational study was conducted in the Department of Histopathology, Liaquat National Hospital and Medical College, from January 2018 till December 2020, over a period of three years. A total of 101 cases with a histopathological diagnosis consistent DLBCL were included in the study. Immunohistochemical (IHC) stains CD10, B-cell lymphoma 6 (Bcl-6), and multiple myeloma oncogene 1 (MUM1) were applied for the further sub-categorization of DLBCL into germinal center B-cell-like (GCB) and non-GCB subtypes according to the Hans algorithm. The Ki67 index was interpreted in hot spots of the tumor and reported as an average percentage. Results Out of 101 DLBCL cases, 47.5% of DLBCL were GCB, while 52.5% were non-GCB subtypes. Bcl-2, Bcl-6, MUM1, c-Myc, CD10, and CD30 expression were noted in 62.4%, 45.5%, 42.6%, 44.6%, 39.6%, and 7.9% cases, respectively. The mean Ki67 index was 72.94±16.69%. The mean Ki67 index in non-GCB-type DLBCL was 77.67±14.80%, which was significantly higher than the mean Ki67 index in GCB-type DLBCL (67.70±17.22%) with a significant p-value (p=0.002). Cervical lymph node was the most common site of DLBCL, while the stomach was the most common extra-nodal site. A significant association of Ki67 index was noted with subtypes of DLBCL. A higher proportion of non-GCB-type DLBCL exhibited greater than 80% Ki67 index than GCB subtype DLBCL. Moreover, a significant association Ki67 index was noted with c-Myc positivity. A higher proportion of c-Myc-positive DLBCL had greater than 80% Ki67 index. Conclusion We found that non-GCB-type DLBCL had a higher Ki67 index than GCB subtype DLBCL, portending a poor prognostic significance of non-GCB subtype of DLBCL. Moreover, c-Myc expression was associated with a higher Ki67 index.
