Richter’s transformation (RT) is a complication of chronic lymphocytic leukemia (CLL) or less commonly, Hairy cell leukemia, into a diffuse large B cell lymphoma.

Diffuse large B-cell lymphoma is the most common type of Non-Hodgkin’s lymphoma.

RT should be suspected in patients with CLL who develop worsening B symptoms

• (fever, night sweats, and unintended weight loss) or
• Rapidly Progressive Lymphadenopathy

Biopsy is required to make the diagnosis and histologic pattern exhibits diffuse large B cells.

In this patient, the biopsy shows the pre-existing CLL, represented by the small lymphocytes, next to diffuse large B cells, which characterizes the transformation of CLL into a large B cell lymphoma.