Abstract
Introduction: Lymphoma is a group of lymphoproliferative malignancies that can originate in B lymphocytes, T lymphocytes, or natural killer (NK) lymphocytes. They account for 3% of all cancer types. The WHO's 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tumours was refined in 2016. This study screened surgically excised or biopsied specimens for lymphoma in lymphadenopathy. This research aimed to classify lymphomas in India based on histopathological and immunohistochemical findings.
Methods: The study included 71 cases suspected/probable/proven to have lymphomas, and H&E-suggestive lymphoid malignancies were recruited. Clinical details, histopathological reports, and lymphoma panel IHC status were analyzed. Age, sex, biopsy site, B-symptom history, and clinical findings were recorded. Paraffin blocks were prepared from biopsy specimens in buffered formalin using standard automated methods. All cases' slides were examined to confirm lymphoma. Tissue blocks were selected for IHC staining. All the slides were evaluated and classified as per the WHO 2016 lymphoma classification.
Results: The mean age of the patients was 44.58 years; 54 patients were males, while 17 were females. 61 of 71 cases were detected to be of NHL, and 10 cases were of HL. Most NHL cases were formed by B cell neoplasms, constituting 72.1%, whereas T cell neoplasms constituted 24.6%. 2 of 61 cases showed CD56 positivity apart from T-cell markers and were categorized as T/NK cell NHL. As per WHO classification, different types of NHL and HL were classified. Among NHL, follicular lymphoma (FL) was predominant with 15 cases, while in CHL, mixed cellularity CHL prevalence was high. Ki67 expression in 15 cases of FL showed 1 case of grade 1, 3 cases of grade 2 and 2 cases of grade 3 follicular lymphoma with a Ki67 index of more than 40%.
Conclusion: Histomorphology and immunohistochemistry help diagnose lymphoma. NHL was more common among nodal and extranodal lymphomas. Men dominated the NHL and HL. Follicular lymphoma (FL) was the most common subtype of B-cell NHL. Most HL patients had mixed-cellularity CHL.

Key words: Lymphoma, Immunohistochemistry, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma