Pyogenic granuloma is a non-neoplastic granulomatous lesion developing in skin and mucous membrane as the result of excessive tissue reaction. The pathogenesis of this lesion remains obscure and differential diagnosis is often difficult. We report a case of pyogenic granuloma that developed in a patient taking an immunosuppressant. A 59-year-old male patient had been diagnosed with relapsing polychondritis 8 years ago and had been receiving immunosuppressant therapy at the department of respiratory medicine for 2 years. He was admitted to the hospital due to aggravation of symptoms and received steroid pulse therapy. After the therapy, he suffered from severe oral mucositis and was referred to our department. Multiple erosive lesions were observed in the oral mucous membrane with erythema of the skin around the mouth. The lesions persisted for 5 weeks in spite of local therapy with beclometasone dipropionate and sodium gualenate hydrate gargle. The patient continuously received therapy with steroid and cyclosporine A. After the oral mucositis improved, a granulomatous lesion developed in the tongue and enlarged gradually. The lesion was excised partly and histologically diagnosed as pyogenic granuloma. It is considered that oral mucositis and cyclosporine A may have contributed to the formation of the lesion.
