Pyoderma gangrenosum due to lenalidomide use for multiple myeloma.

Pyoderma gangrenosum has been described in association with multiple myeloma and usually affects patients with active/untreated disease. This dermatologic condition was shown to resolve after successful anti-myeloma therapy. We report herein occurrence of pyoderma gangrenosum involving bilateral knees in a patient with multiple myeloma responding to lenalidomide therapy. Previous papers claimed usefulness of thalidomide and its newer derivatives for the therapy of this neutrophilic dermatosis. Occurrence of pyoderma gangrenosum in a myeloma patient responding to lenalidomide would argue against its effectiveness in treating this skin condition. Moreover, the clinical setting suggested that lenalidomide either induced or contributed to the occurrence of pyoderma gangrenosum in our patient. If our hypothesis is correct, we expect more reports of pyoderma gangrenosum with the use of this class of pharmaceuticals.