'Leukaemic pernio': perniosis-like presentations of chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL) is the most common type of leukaemia in adults. Skin involvement by malignant CLL cells, or leukaemia cutis, typically presents as localized or generalized papulonodular lesions. We report a series of five patients with CLL who presented with perniosis-like skin findings on the ears, nose and/or digits. Histopathological analysis of seven skin specimens from these five patients showed a relatively dense, nodular to diffuse, pandermal infiltrate of monomorphic lymphocytes, compatible with CLL. The typical histopathological findings of perniosis, such as a robust perivascular and peri-eccrine infiltrate, dermal oedema and interface change, were absent. In one patient, the skin findings heralded the diagnosis of CLL. In most patients, the skin lesions tended to improve with systemic treatment of the patient's underlying CLL. We suggest the term 'leukaemic pernio' for leukaemia cutis that clinically mimics perniosis.