Anti-CD20 Monoclonal Antibody (Rituximab) for Therapy of T-Cell/Histiocyte-Rich Large B-Cell Non-Hodgkin Lymphoma.

T-cell/histiocyte-rich large B cell lymphoma (THR-BCL) is morphologic variants and subtypes of diffuse large B cell lymphoma (DLBCL). Four immunomorphologic criteria were applied to distinguish THR-BCL from DLBCL.

1. a diffuse or vaguely nodular pattern of neoplastic infiltrate,

2. the presence of scattered large atypical lymphoid cells that are of B-cell phenotype,

3. predominance of a reactive background infiltrate, composed of both T-cell and non-epithelioid histiocytes,

4. minimal presence of small B-cells in neoplastic areas.

Bcl-6 protein expression, which was generally accepted markers of germinal center differentiation, was noted more than half of the THR-BCL cases. THR-BCL predominantly affected middle-aged men who present with advanced disease and an unusually high percentage of bone marrow (BM) involvement. Here we report a pediatric case of THR-BCL. 14-year-old boy was presented with both cervical mass which was observed 1 month ago. He complained generalized weakness and chest discomfort had fever. Cervical lymph node and BM biopsy were taken. Laboratory finding was as follows; Hemoglobin 10.4 mg/dL, hematocrit 31 %, leukocyte 6,730/μL, platelet 219,000/μL. Na 128 mmol/L, K 4.6 mmol/L, Cl 95.4 mmol/L, BUN 10 mg/dL, Cr 1.2 mg/dL, LDH 2,108 U/L. Lymph node specimen showed diffuse large B cell lymphoma and numerous histiocytes. Immnuohistochemical staining; CD 20(+), CD 10(−), CD 3(+), CD 68(+). Ann Arbor stage is IVB, international prognostic index is high-intermediate risk. He received induction chemotherapy with prednisolone, vincristine, cyclophosphamide, doxorubicin, rituximab and achieved remission and now he have continued chemotherapy for 7 months in state of complete remission. THR-BCL is a distinct clinicopathologic entity within DLBCL that is characterized by an aggressive behavior and high risk of treatment of failure. That is the reason why delineate this subgroup. Experimental therapeutic strategy was indicated in patients who relapsed after having obtained a complete remission or had partial response after initial chemotherapy.