Morphological and IHC findings favored the diagnosis of medullary infiltration by a non-Hodgkin lymphoma of large B cells (CD20+), with aberrant CD5 staining, which correlated with clinical and laboratory findings, making the diagnosis of a diffuse large B-cell lymphoma (DLBCL), a non-Hodgkin lymphoma of B-cell origin. Here, CD5 is linked to non-Hodgkin lymphoma.