Review of the Sub Classification of Lymph Node Biopsies Reported as Reactive Lymphadenitis at Kenyatta National Hospital

Abstract

Background: Lymphadenopathy is a common clinical finding in both adult and paediatric patients in Kenya. It has a broad differential diagnosis, the most common being nonspecific reactive lymphoid hyperplasia, a benign reversible enlargement of the lymph node which often disguises malignancy. It is known to be of unknown cause. Prevalence and morbidity of malignancies in early stages e.g. micro lymphoma in diagnoses of reactive lymphadenitis have been poorly investigated. Objective: To evaluate the histopathologic patterns of lymph node biopsies reported as reactive lymphadenitis at Kenyatta National Hospital for the period 2013-2019. Methods: The study utilized formalin fixed paraffin embedded tissue blocks of lymphadenopathy, previously reported only as reactive lymphadenitis on histopathology, in the department of human pathology at KNH. Consent to conduct the study was obtained from KNH/UoN ERC. The demographic and clinical data were retrieved from the records. Haematoxylin and eosin was performed to confirm the initial reported diagnosis of non-specific reactive hyperplasia. Further characterization was done through immunohistochemistry evaluation. Data was entered into excel spreadsheet, cleaned and analyzed using SPSS version 20 for statistical correlations. Results: The study analyzed 86 cases, 64 (73%) which were adults and 22 (27%) paediatric cases. The age range was 1year 3months to 76 years. Out of the 86 cases, males were 49 (57%), while females were 37 (43%). Follicular hyperplasia 63 (73%), sinus expansion 16 (19%) and progressive transformation of germinal center (PTGC) (1%) were the histopathological patterns of reactive lymphadenitis in the studied cases. Diffuse and mixed patterns were not found among the reviewed cases, and no cases of micro lymphomas were reported in the current study. However, 6(7%) cases were of notable pathology, which were confirmed using immunophenotyping to be DLBCL (1 case), a high grade round blue cell tumor of childhood (1 case), and 4 (3SLL and 1MCL) cases of lymphomas. Discussion: Follicular hyperplasia was the most predominant sub-classification of cases reported as reactive lymphadenitis in KNH. Further studies to correlate histopathological patterns of reactive lymphadenitis with underlying cause are recommended. IHC is useful when morphologic features are equivocal. Minimum markers that would help improve lymphoma diagnosis in our set-up would include CD20, CD10, CD3, Ki-67, Bcl2, and Bcl6 to differentiate a reactive process from a lymphoma. Conclusion: This study underscores the need for routine use of the various sub-classifications of reactive lymphadenitis in the diagnosis as they may suggest the underlying pathological condition