[Cutaneous transformation of chronic lymphoid leukemia into immunoblastic lymphoma. Cutaneous manifestation of Richter syndrome].

INTRODUCTION: Richter's syndrome is a large-cell lymphoma occurring in patients with chronic lymphoid leukaemia (CLL). It is rarely limited to cutaneous locations. We report the case of a 61-year-old patient with CLL who developed multiple skin lesions due to immunoblastic lymphoma. CASE REPORT: Six years after onset of CLL controlled by chloraminophen, a tumoural syndrome developed and was treated by chemotherapy. A papulonecrotic cutaneous eruption was then observed on the face, the presternal area and then on the fingers. Skin biopsy revealed large-cell CD20+ CD30+ immunoblastic lymphoma. Polymerase chain reaction on the heavy chain immunoglobulins showed a band with the same size in the skin biopsy and in the circulating cells. No transformation was found in lymph node and bone marrow biopsies. The lesions disappeared after 4 treatments with VP16, cysplatin and methylprednisolone. CLL was again stabilized after the first chemotherapy sessions. DISCUSSION: Richter's syndrome is rarely discovered due to skin lesions. There have only been 4 similar cases reported in the literature. The clinical presentation of the lesions is insufficient to distinguish them from manifestations of CLL. Histological examination of the biopsy is required to make the diagnosis of high grade lymphoma. Prognosis is usually poor after discover of this type of lymphoma. This is the first observation of Richter's syndrome revealed by a skin lesion in which polymerase chain reaction suggested that the skin lymphoma and the CLL cells came from the same B clone.