ABSTRACT
T-cell prolymphocytic leukemia (T-PLL) is a rare mature T-cell lymphoproliferative disorder that affects adults, occurs more frequently in men, and is characterized by an aggressive clinical course and a poor outcome. T-PLL is composed of small- to medium-sized lymphocytes with prominent nucleoli. Alemtuzumab is an effective agent in T-PLL and represents a significant improvement over other types of therapy. T-PLL involvement of the lymph node is usually paracortical with preserved follicles and patent sinusoids, but may be diffuse with total effacement of lymph node architecture. T-PLL is genetically characterized by the presence of complex karyotypes. In the blood and bone marrow, the differential diagnosis of T-PLL includes B- and T-cell disorders composed of small- to medium-sized lymphocytes, reactive lymphocytosis, and occasionally acute leukemias. B-cell lymphomas with leukemic blood involvement are distinguished from T-PLL by expression of B-cell antigens, surface immunoglobulins, and Human leukocyte antigens-DR. Eosinophilia is more typical for Sézary’s syndrome, as it is rarely seen in T-PLL.
