Introduction: The diagnosis of chronic lymphocytic leukemia/ small lymphocytic lymphoma (CLL/SLL), which also includes atypical forms, can be very difficult. The aim of this study is to compare immunohistochemical (IHC) and flow cytometric (FC) immunophenotyping methods in the CLL/SLL, the most common mature B-cell leukemia/lymphoma of adults, in bone marrow biopsy. In these two methods, it is to determine the minimum panels that can differentiate CLL/SLL from other mature B-cell leukemia/lymphomas. Material and Method: The study included 68 adult patients diagnosed with mature B cell leukemia/lymphoma. Final diagnoses were made on the basis of peripheral smear, bone marrow aspirate, bone marrow biopsy, IHC and FC analysis, clinical and genetic studies. Cell counts, final diagnosis and immunophenotyping were compared with both methods. Cytogenic findings were evaluated. The sensitivity, specificity, positive and negative predictive values of IHC and FC results for CLL/SLL were calculated. Results: CLL/SLL was diagnosed in 64.7% of the cases and non- CLL/SLL in 35.29% of the cases. The median age was 66.50 years, 69.18% male and 30.82% female. The diagnosis compatibility in FC and IHC was found to be highest in hairy cell leukemia/lymphoma with 100%, and in CLL/SLL with 90%. In other lymphomas, a definitive diagnosis could only be made with biopsy. Immunophenotyping made with CD23+CD43+CD5+LEF-1 in the bone marrow biopsy showed a sensitivity of 95.45% (range, 84.53-99.44%) and a specificity of 100.00% (range, 85.75-100.00%) for CLL/SLL. Immunophenotyping made with CD23+CD43+CD5+CD200+ in FC showed a sensitivity of 100.00% (range, 91.96-100.00%) and a specificity of 82.61% (range, 61.22-95.05%) for CLL/SLL. Conclusion: This was the most extensive study to have compared immunophenotyping in IHC and FC in bone marrow biopsies of mature B cell leukemia/lymphoma. The addition of LEF-1 to the CD23(+), CD43(+), CD5(+) panel in IHC and the addition of CD200 to the same panel in FC will be extremely helpful in the differential diagnosis of typical/atypical CLL/SLL from mature B cell leukemia/lymphoma.

Introduction: Waldeyer's ring (WR) is the second most common site of extranodal lymphomas. Its clinical course may resemble those of nodal lymphomas. In this study, we evaluated the histopathological and clinical findings, the presence of Epstein-Barr virus (EBV), and overall survival of WR lymphomas diagnosed in our department. Materials and Methods: Retrospectively, 32 patients diagnosed with WR lymphoma between 2017-2022 were included. The demographic, clinical data of the patients and lymphoma types according to the latest classification of the World Health Organization, the presence of EBV (EBV early RNAs (EBER) by chromogenic in-situ hybridization (ISH) method) were examined. Descriptive statistics, categorical data were evaluated as percentage and frequency. Kaplan-Meier analysis was used for survival rate. A P value less than 0.05 was considered statistically significant. Results: The majority of 32 cases in our study were male. The mean age was 57.97±16.15 years. The clinical prediagnosis was carcinoma in 46.9% of the cases. Tonsil and nasopharynx had equal proportions as lymphoma origin. Only 3 (9.4%) cases are classic hodgkin lymphoma (CHL). Others were NHL, of which 16 (50.0%) were diffuse large B-cell lymphoma (DLBCL). EBER was positive only in tonsillar CHL cases. The survival of patients with lymphoma of nasopharyngeal origin was shorter than those of tonsillar origin (p=0.037). Conclusion: WR lymphomas are most often confused with carcinomas clinically. DLBCL is the most common type of lymphoma. EBER has been detected only in CHL. Survival is lower in lymphomas originating from the nasopharynx. Keywords: Non-Hodgkin Lymphoma, Nasopharynx, Tonsil, Hodgkin Lymphoma