Imiquimod for restoring local immunity in a renal transplant patient with persistent keratoacanthoma

Keratoacanthoma (KA), a cutaneous neoplasm histologically resembling squamous cell carcinoma, is characterized by rapid growth and common spontaneous regression. The regression depends on an individual's immune response. We are reporting a case of a 53-year-old man who presented with an ulcerated tumor, which had arisen as a nodular lesion 9 months earlier. This was localized on the the left thumb. The patient had undergone a kidney transplant after severe glomerulonephritis. Following the operation, he was treated with systemic immunosuppressive drugs and developed multiple nonmelanoma skin cancers. The histology examination of biopsy specimens was consistent with keratoacanthoma and showed low-density chronic inflammatory cells. Our patient refused surgical excision, so we prescribed imiquimod 5 percent cream once daily for 5 days a week. After 6 weeks of treatment the lesion had regressed completely, yielding an excellent cosmetic result. Continued resolution was documented 3 years after treatment. The patient had no signs of graft rejection related to the imiquimod treatment. © 2008 Dermatology Online Journal.