Case 15 - Discussion

Uploaded: 2007-06-27, Updated: 2007-06-27

   
Ki67 CD15
CD20 CD30
CD5 CD79a
 
EBV

 

   
 
 

Hodgkin’s disease variant of Richter’s transformation

 

CASE PRESETATION

Microscopically, sections  perihilar lymph nodes show predominant involvement of small lymphocytes, consistent with CLL. In addition, some large pleomorphic cells resembling Hodgkin and Reed-Stemberg cells are occasionally seen among the CLL infiltrates. The CLL cells are positive for CD79a, weak CD20 and CD5, and negative for CD3, and the large H-RS cells are positive for CD79a, CD20, CD30, CD15, EBV-LMP and weak PAX5.

 

DISSCUSSION

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia worldwide. It is an indolent disease, almost exclusively of B-cell origin. Some CLLs may transform into a more aggressive lymphoid malignancy, with the most common of these is Richter's syndrome. Richter's transformation denotes the development of high-grade non-Hodgkin lymphoma, prolymphocytic leukemia, Hodgkin disease, or acute leukemia in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma. Most Richter's syndrome cases are secondary diffuse large B-cell lymphomas, but some are Hodgkin's disease variants. Richter's syndrome occurs in approximately 5% of patients with CLL.

 

Richter's syndrome may be triggered by viral infections, especially Epstein-Barr virus, and it is also associated with some chromosomal abnormalities and genetic defects, including trisomy 12, chromosome 11 abnormalities, mutations of p53 tumor, p16INK4A, and p21, loss of p27 expression, deletion of retinoblastoma, increased copy number of C-MYC, and decreased expression of the A-MYB gene, expression of activation-induced cytidine deaminase (AID), and aberrant somatic hypermutation (ASHM). The large cells of RS may arise through transformation of the original CLL clone or represent a new neoplasm.

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