A T-cell prolymphocytic leukemia case with central nervous system involvement.

T-cell prolymphocytic leukemia (T-PLL) is an aggressive mature T cell neoplasm that typically involves peripheral blood, bone marrow, lymph nodes and spleen. It is a rare disease that comprises 2-5% of mature lymphocytic leukemia in adults. Here we present a T-PLL patient with CNS involvement. A 74-year-old man admitted to a hospital in April 2014 with vomiting. He was diagnosed as chronic lymphocytic leukemia (CLL) and R-CVP (Rituximab, cyclophosphamide, vincristine and prednisolone) chemotherapy protocol was started. After the first two cycles of chemotherapy, the patient's mental functions improved. However after the 3(rd) cycle of chemotherapy was given in July 2014 the general situation of the patient deteriorated and ptosis of the left eye and facial paralysis developed. Then the patient was referred to our medical center. An MR of the brain revealed linear contrast enhancement around the bilateral 3(rd), 7(th) and 8(th) cranial nerves which indicated cranial involvement by the lymphoproliferative process (Figure 1). Cerebrospinal fluid cytological examination confirmed the diagnosis. Based on these and bone marrow aspiration and biopsy findings a diagnosis of T-PLL was rendered (Figure 3). In September 2014 the patient died suddenly due to a cardiac arrest. Differential diagnosis is very important in T-PLL. Both T-PLL and chronic lymphocytic leukemia (CLL) may present with splenomegaly and lymphocytosis as well as circulating prolymphocytes in blood. Typical CLL cells are like mature lymphocytes with dense nucleus and aggregated chromatin. To conclude, CNS involvement in T-PLL is a rare finding and differential diagnosis of T-PLL is very important.