Objective: Non-Hodgkin lymphoma (NHL) is a group of neoplastic lymphoproliferative disease originating mainly in the lymph nodes with numerous clinical manifestation and histological features. This study was intended to determine the pattern of extra nodal involvement in Non-Hodgkin’s lymphoma (NHL) in a tertiary care hospital, Karachi.

Methodology: This was a cross-sectional study conducted at the Department of clinical oncology, Jinnah postgraduate medical Centre, Karachi by using non-probability consecutive sampling technique. The duration of the study was about 6 months from Nov 2020-May 2021. A total of 78 adult patients of age between 17 to 71 years of either gender with biopsy proven diagnosis of NHL were included in the study. Chi-square test was used to assess the significance between age, gender, stage of NHL, bone marrow and lymph node involvement with pattern of extra nodal involvement.

Results: The study results showed, out of 78, 53(67.9%) were males whereas 25(32.1%) were females with their mean age was 46.71±14.36 years. Frequency of Extra-nodal Sites of involvement showed that paravertebral fascia 8(10.3%) was the most frequent anatomical site of NHL, followed by thigh 7(9%), femur 5(6.4%), tonsils 4(5.1%). Histologically, Diffuse large B cell lymphoma (DLBCL) reported in about 52(66.7%) of all the cases, 14(17.9%) had B cell, 9(11.5%) had follicular lymphoma while only 3(3.8%) had Marginal zone lymphoma (MZL). Furthermore, there was a significant association observed between morphological types with gender (p=0.012), with stage of disease (p=0.001) and with lymph node involved (p=0.012).

Conclusion: This study concluded that diffuse large B cell lymphoma was the most common morphological type observed. Paravertebral fascia and thigh were the most common anatomical sites for extranodal involvement in Non-Hodgkin lymphoma. Most of the cases were at stage IE with better prognosis and survival rate. Moreover, significant differences were found in the pattern of extra nodal Non-Hodgkin lymphoma.

Keywords: Extra nodal lymphoma, Morphological pattern, Non-Hodgkin’s Lymphoma.