Beyond Classic Leukemia Cutis: Evidence of Leukemic Cell "Spillover"

Leukemia cutis is defined as involvement of the epidermis, dermis, and subcutaneous tissue with a systemic leukemia. It is associated with a poor prognosis and can be a sign of advanced leukemia. This case series describes a distinct pattern of leukemic cell involvement in the skin that differs from classic leukemia cutis. These cases are characterized by a sparse leukemic cell infiltrate typically associated with an underlying inflammatory tissue reaction pattern. This is suggestive of "spillover" rather than primary infiltration. This phenomenon may not uniformly carry the same poor prognosis as classic leukemia cutis and emphasizes the need for further research to guide diagnosis and management.