Leukemia cutis in a patient with chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative disorder. Less than 50 cases have been reported. We report the first case of CNL with an associated leukemia cutis. CNL was diagnosed in a 74-year-old white woman in 1998, based on neutrophilic infiltration of the bone marrow and absence of the Philadelphia chromosome. The patient presented to the dermatology service in August 1998 with a 2-week history of a pruritic eruption on the arms, hands, and legs. Physical examination revealed red to violaceous plaques on both thighs and knees, in addition to purpuric patches and plaques on the dorsal hands, arms, and legs. Leukemia cutis was demonstrated on biopsy specimens of several lesional sites. The eruption progressed, despite treatment with topical and systemic corticosteroids. Treatment with systemic chemotherapy did affect partial resolution of the eruption, with parallel decreases in bone pain and white blood cell count, but the disease progressed and the patient ultimately died 5 months after her initial skin findings. Only one other case of CNL with dermatologic manifestations has been reported, CNL associated with a reactional neutrophilic dermatosis. Comparison to and differentiation from this case is discussed. The importance of distinguishing the specific infiltrates of leukemia from the nonspecific infiltrates of reactional dermatoses, such as Sweet's syndrome, is illustrated.