Abstract
This case describes a patient with known mantle cell lymphoma without cutaneous involvement presenting with a diffuse morbilliform rash during an inpatient admission for bacterial pneumonia. The patient was thought to have a hypersensitivity to antibiotics but failed to improve after the offending agents were stopped. A skin biopsy revealed metastatic cutaneous mantle cell lymphoma. Treatment with high-dose corticosteroids and chemotherapy was initiated resulting in the resolution of the rash.