Cutaneous presentation of chronic lymphocytic leukemia as unique extramedullar involvement in a patient with normal peripheral blood lymphocyte count (monoclonal B‐cell lymphocytosis)

Abstract

Skin infiltration by chronic lymphocytic leukemia (CLL) is very rare and almost all reported cases occur in advanced stage. We report a patient with no relevant past medical history who presented with cutaneous erythematous plaques. A punch biopsy showed typical CLL morphologic and immunophenotypic features. Subsequent studies revealed a normal lymphocyte count in peripheral blood, and there was no evidence of lymphadenopathy or organomegaly. Flow cytometry demonstrated a clonal B-cell population both in the bone marrow and peripheral blood (1.60 × 10(9)/l) with a CLL phenotype, but it did not fulfill required criteria for CLL diagnosis. Without cutaneous involvement, this case should be classified as monoclonal B-cell lymphocytosis.