Patterns of bone marrow infiltration in lymphomas- A retrospective descriptive analysis from a tertiary care centre in Southern India

Bone marrow biopsy (BMB) examination is the gold standard for staging of lymphoma which is interpreted along with other clinical, laboratory and radiological investigations. This study aimed to evaluate the various patterns of BMB infiltration by lymphomas which include Hodgkin and Non Hodgkin lymphoma and the usefulness of BMB compared to bone marrow aspiration (BMA). : In a period of three years, there were 212 cases which showed lymphoma infiltration in bone marrow. We assessed the peripheral blood smear (PBS), BMA and BMB slides and concordance between each was evaluated. BMB slides were assessed for the pattern of involvement. The most frequent subtype was chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) (21.70%) followed by Hodgkin lymphoma (HL)(12.73%)and follicular lymphoma (FL)(11.32%). Predominant pattern of infiltration showed by CLL/SLL cases was mixed pattern, by FL was paratrabecular pattern, mantle cell lymphoma(MCL) showed either diffuse or nodular, diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma(BL) showed predominantly diffuse pattern. Hairy cell leukemia (HCL) and peripheral T cell lymphoma (PTCL) showed an interstitial pattern. In HL, the pattern was usually focal nodular however diffuse involvement was seen in a few. Of the 212 cases, 50.94% cases had atypical lymphocytes or lymphocytosis in PBS and 81.14% cases showed infiltration in BMA. Atypical lymphoid cells may not be present at times in peripheral blood or bone marrow aspirate in spite of infiltration in the bone marrow. Different lymphomas show characteristic patterns of marrow involvement.