Leukemia Cutis at the Diagnosis of Chronic Lymphocytic Leukemia: A Case Report

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Specific cutaneous infiltration by leukemic cells is rare and, in exceptional cases, can be the presenting manifestation of the disease. We report the case of a 73-year-old man referred for lymphocyte-predominant hyperleukocytosis associated with infiltrated erythematous plaques on the left leg. Clinical examination found no tumor syndrome. The blood count showed hyperleukocytosis (298,000/mm³), severe anemia (hemoglobin, 4.6 g/dL), and profound thrombocytopenia (5,000/mm³). Blood immunophenotyping revealed a B-lymphoid clone consistent with typical CLL. Skin biopsy showed an atypical dermal lymphoid infiltrate, and immunohistochemistry (CD5+, CD20+, CD23+) was consistent with specific cutaneous involvement by CLL. Immunochemotherapy with rituximab, cyclophosphamide, and dexamethasone was initiated, resulting in marked improvement of the skin lesions after four cycles of treatment. Specific cutaneous infiltration is a rare manifestation of CLL and can, exceptionally, be the presenting feature of the disease. This case highlights the value of performing a skin biopsy for any atypical skin lesion associated with lymphocytosis.