Richter's transformation
Medical condition / From Wikipedia, the free encyclopedia
Richter's transformation (RT), also known as Richter's syndrome, is the conversion of chronic lymphocytic leukemia (CLL) or its variant, small lymphocytic lymphoma (SLL), into a new and more aggressively malignant disease.[1] CLL is the circulation of malignant B lymphocytes with or without the infiltration of these cells into lymphatic or other tissues while SLL is the infiltration of these malignant B lymphocytes into lymphatic and/or other tissues with little or no circulation of these cells in the blood.[2] CLL along with its SLL variant are grouped together in the term CLL/SLL.[1]
Richter's transformation | |
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Other names | Richter's syndrome |
Specialty | Hematopathology, Oncology, Surgical oncology |
Types | Diffuse large B-cell lymphoma type, Hodgkin's lymphoma type |
Prognosis | Poor |
Frequency | rare |
RT is diagnosed in individuals who have CLL/SLL that converts to a malignancy with the microscopic histopathology of diffuse large B-cell lymphoma (DLBCL) or, less commonly, Hodgkin’s lymphoma (HL).[3] There are rare cases of: 1) CLL/SLLs that convert into lymphoblastic lymphoma, hairy cell leukemia, or a high grade T cell lymphoma[4] such as anaplastic large-cell lymphoma or angioimmunoblastic T-cell lymphoma;[5] 2) CLL/SLLs that convert into acute myeloid leukemia;[6] 3) CLL/SLLs that convert into or develop non-hematological malignancies such as lung cancer, brain cancer, melanoma of the eye or skin,[5][7] salivary gland tumors, and Kaposi's sarcomas;[8] and 4) conversion of follicular lymphoma, lymphoblastic lymphoma, or marginal zone lymphoma into other types of hematological malignancies.[9] While some of these conversions have been termed RTs, the World Health Organization[10] and most reviews have defined RT as a conversion of CLL/SLL into a disease with DLBCL or HL histopathology. Here, RTs are considered to be CLL/SLLs which convert into a disease with either DLBCL histopathology (here termed DLBCL-RT) or Hodgkin's lymphoma histopathology (here termed HL-RT).
CLL/SLL is the most common adult leukemia in Western countries, accounting for 1.2% of the new cancers diagnosed each year in the United States. It usually occurs in older adults (median age at diagnosis 70) and follows an indolent course over many years.[11] About 1-10% of CLL/SLLs develop a Richter's transformation at a rate of 0.5–1% per year. In earlier studies, the transformed disease was reported to be far more aggressive than CLL/SLL with overall median survival times (i.e. times in which 50% of cases remain alive) between 1.1 and 16.3 months. Newer therapeutic regimens are improving the prognosis of DLBCL-RT and HL-RT.[12]