Eccrine squamous syringometaplasia (ESS) has been associated with characteristic clinical eruption in patients receiving chemotherapy. It has been suggested as a diagnostic clue in the diagnosis of chemotherapy-induced reactions vs acute graft-vs-host disease, as well as other drug reactions. We identified 10 cases of ESS in patients in whom a distinctive clinical eruption developed during or after a pretransplantation conditioning regimen with high-dose chemotherapy. A complete clinical and histologic evaluation was performed in all patients.