T-Cell Prolymphocytic Leukemia: A Rare Disease With an Aggressive Clinical Course

• Published in: American journal of clinical pathology 2018-09, Vol.150 (suppl_1), p.S105-S106
• Main Authors: Zhang, Lin, Massey, Daphne, Jaitly, Vanya, Wang, Xiaohong
• Format: Article
• Language: English
• Subjects: Bacteremia; Bone marrow; CD4 antigen; CD8 antigen; Cytogenetics; Cytology; Cytoplasm; Differential diagnosis; Drug resistance; Flow cytometry; Karyotypes; Leukemia; Leukocytosis; Lymph nodes; Lymphadenopathy; Lymphocytes T; Malignancy; Monoclonal antibodies; Nucleoli; Patients; Peripheral blood; Rare diseases; Renal failure; Spleen; T cell receptors; Thrombocytopenia
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1093/ajcp/aqy097.255

Abstract T-cell prolymphocytic leukemia (T-PLL) is an aggressive mature postthymic T-cell leukemia characterized by the proliferation of small- to medium-sized prolymphocytes with distinctive clinical, morphologic, immunophenotypic, and cytogenetic features. It usually involves the peripheral blood, bone marrow, lymph nodes, liver, and spleen. It is a very rare disease that represents 2% of mature lymphocytic leukemias in adults over the age of 30. Because of the aggressive and rapid clinical course of this disease, correct diagnosis and prompt treatment are very important in T-PLL. Patient is a 33-year-old man with a recently diagnosed T-cell malignancy in the lymph node from an outside hospital presenting with generalized lymphadenopathy, hepatosplenomegaly, leukocytosis, and severe thrombocytopenia. He was put on hyper-CVAD. Peripheral blood smear comprised predominant atypical lymphocytes with very irregular nuclear contours, some with prominent nucleoli, and scant amount of blue-gray cytoplasm with cytoplasmic blebs. Immunophenotyping by flow cytometry showed CD4–, CD8+, mature T cells comprising 93% of the bone marrow cells with no loss of pan–T-cell markers. Immunohistochemical stain for TCL1 was strongly positive. T-cell receptor rearrangement was positive for beta rearrangement. Cytogenetic analysis revealed a complex abnormal karyotype. Based on all the features, a diagnosis of T-PLL was made. Treatment with campath (alemtuzumab) and possible allogenic stem cell transplant were initiated based on the diagnosis. However, the patient did not respond well to campath, and his treatment has been complicated by CMV viremia, MRSA bacteremia, acute renal failure, and severe deconditioning. In conclusion, T-PLL is a very rare and aggressive mature T-cell leukemia with special treatment plans. Differential diagnosis and prompt treatment of T-PLL are very important. The distinctive features of morphology, no loss of pan–T-cell marks, TCL1 expression, and cytogenetics studies will be helpful to reach a correct diagnosis.