Richter transformation

Richter transformation is defined as the development of high-grade non-Hodgkin lymphoma (NHL) in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL).

It has been expanded to include other lymphoid malignancies that develop in CLL patients, including Hodgkin disease, prolymphocytic leukemia (T-PLL), the Hodgkin variant of Richter transformation, small non-cleaved cell lymphoma, lymphoblastic lymphoma, and hairy cell leukemia . Lymph node biopsy is required for the diagnosis of Richter transformation.

Epidemiology

Richter transformation is observed in about 5-10% of patients with chronic lymphocytic leukemia .

Clinical presentation

Patients present with an aggressive disease course, with rapidly enlarging lymph nodes, hepatomegaly, splenomegaly, and elevated serum lactate dehydrogenase (LDH) levels. Systemic symptoms include weight loss, fever, and drenching night sweats. Abdominal pain may be a consequence of further hepatic and/or splenic enlargement.

Pathology

The nodal disease can potentially occur anywhere in the body. The disease can also present as distinct mass-like lesions .

Extranodal involvement is rare and can involve the gastrointestinal tract, central nervous system, skin, eye, lung, kidney, or testis.

Etiology

The molecular mechanisms involved are poorly understood. Richter transformation may be triggered by viral infections, common in immunosuppressed patients, such as Epstein-Barr infection. Multiple genetic defects have been described that may cause CLL cell proliferation and eventual transformation .

Radiographic features

CT

Development of lymphadenopathy, particularly retroperitoneal, and splenomegaly in a context of known CLL.

Nuclear medicine

PET-CT may play a role and nodes show high FDG uptake  .

Treatment and prognosis

Treatment strategies include chemotherapy regimens given for aggressive lymphoma or acute lymphoblastic leukemia (ALL), with or without monoclonal antibodies, allogeneic stem cell transplantation, and, rarely, radiotherapy.

The disease responds poorly to therapy. Prognosis is poor, with a mean survival duration of 5-8 months for patients on therapy .

History and etymology

It was first described by the American pathologist, Maurice N Richter (1897-1988) in 1928, who worked at New York University Medical Center .