FINAL DIAGNOSIS: DIFFUSE LARGE B- CELL LYMPHOMA, MONOMORPHIC, PTLD
Post transplant lymphoproliferative disorders (PTLD) is a term encompassing a range of lymphoproliferations associated with immunosuppression (1,2,3,4). Approximately, 2-5% of transplant patients can develop PTLD (1). This can vary from <1% in renal allografts to almost 20% in patients with immunosuppressed bone marrow allografts for graft vs. host disease. There is a frequent association with Epstein-Barr virus as well, with about about 80% of cases demonstrating positivity for the virus. The majority of high grade PTLD's are of clonal B-cell origin with rare T-cell proliferations.
Most patients with PTLD usually present within one year of transplantation. EBV negative PTLD's tend to present later (1). Clinically, diffuse lymph adenopathy is a common sign. Symptoms may vary from fever and malaise to organ involvement effects. The latter can include organ failure, hemorrhage or CNS effects as in this patient.
Currently, PTLD is divided into four classifications (1,4). These include early lesions, polymorphous PTLD, monomorphic PTLD and Hodgkin / Hodgkin-like PTLD. Early lesions include plasmacytic hyperplasias and infectious mononucleosis. Polymorphous PTSD's include destructive lesions composed of immunoblasts, plasma cells and intermediate cells with architectural effacement of lymph nodes. Monomorphous PTSD's are considered non-Hodgkin's lymphomas. The majority of these are diffuse large B-cell lymphomas as in this case. A minority may represent Burkitt lymphomas. Finally, PTSD's that appear to have a Hodgkin's like appearance are called either Hodgkin's or "other".
In this case, the large lymphocytes with high mitotic activity suggested a higher grade lymphoma. Clonality was confirmed by kappa and lambda stains. The presence of CD 20 positivity in large cells and CD3 negativity in the small cells suggested a B cell neoplasm. TDT negativity reduced the likelihood of ALL relapse. Eber positivity favored an EBV related PTLD process.
Contributed by Raj Hari, MD