Transient leukaemia cutis in chronic lymphocytic leukaemia.

Leukaemia cutis arises from cutaneous infiltration by neoplastic leukocytes or their precursors. Recent evidence suggests that this sign does not necessarily herald a poor prognosis. We describe a 72-year-old woman with B-cell chronic lymphatic leukaemia who developed a papular eruption of her breast at the site of a recent herpetic eruption. Histology and immunostaining showed a dense dermal B-cell infiltrate in keeping with leukaemia cutis. The papules cleared in 6 months without treatment, leaving atrophic scars. The histological features and possible aetiological mechanisms of post-herpetic papular eruptions in chronic lymphatic leukaemia are reviewed.