The diagnostic study of choice for non-Hodgkin lymphoma is excisional lymph node biopsy. A bone marrow biopsy is an alternative to a lymph node biopsy. According to the Ann Arbor system with Cotswald modifications, there are four stages of non-Hodgkin lymphoma based on the number of nodes and extra nodal involvement.
In addition to light microscopy evaluation of the excisional biopsy samples, the immunophenotypic analysis with immunohistochemistry helps to determine non-Hodgkin's lymphoma subtypes and distinguish non-Hodgkin's lymphoma from T cell rich large B cell lymphoma and anaplastic large cell lymphoma.[2]
The presence of CD20 positive clonal B cells defines non-Hodgkin lymphoma.[3]
In about 40% of adult patients with non Hodgkin lymphoma, the extranodal sites are the primary presenting sites with the most common site being the Gastrointestinal tract.[3]
A bone marrow (BM) biopsy can also be done to diagnose non-Hodgkin lymphoma if there is sufficient evidence of marrow involvement such as presence of cytopenias.[3]
Non-Hodgkin lymphoma cells originate in the bone marrow, which is the site of B cell production and maturation.
Bilateral BM biopsy has been recommended with trephine biopsy being preferred to marrow aspiration for detecting marrow infiltration.[4][5]
BM biopsies, performed under local anesthesia, were obtained using the conventional technique with a Jamshidi needle from the posterior superior iliac spines, fixed in 10% formalin solution and decalcified using 10% formal - formic acid for 4 - 6 h followed by routine processing and paraffin embedding.[6]
According to the Ann Arbor staging system with Cotswald modifications, there are four stages of non-Hodgkin lymphoma based on the number of nodes and extra nodal involvement. Staging for non-Hodgkin lymphoma is provided in the following table:[7][8]
Ann Arbor staging system
Stage
Involvement
stage I
I
One nodal group or lymphoid organ (e.g. spleen or thymus)
IE
One extra nodal site
stage II
II
Two or more nodal groups, same side of diaphragm
II E
Localized extra nodal site with stage II criteria, both on the same side of the diaphragm