The patient went on to have a biopsy that confirmed the diagnosis of post-transplant lymphoproliferative disorder.
Histology
The biopsy shows diffuse infiltration by large pleomorphic lymphoid cells which show strong uniform expression of B cell marker CD20.
Final diagnosis:
Post-transplant lymphoproliferative disorder, diffuse large B-cell lymphoma type, EBV negative.
Note: It should be noted that the majority of these tumors in the post-transplant setting are EBV positive.