Successful treatment of refractory pyoderma gangrenosum with ustekinumab only after excision of renal cell carcinoma.

Dear Editors, Pyoderma gangrenosum is a rarely diagnosed neutrophilic disease, which is clinically characterised by very painful ulcers with violaceous, undermined borders (1–3). Even if aetiology and pathogenesis are still not completely understood an association with other systemic diseases, especially inflammatory bowel diseases, was frequently reported. Currently, other relevant comorbidities, such as rheumatic arthritis, renal dysfunctions, endocrinological and haematological diseases or neoplasms, have been described (3–5). We report a 71-year old patient first presented to our outpatient clinic 4 years ago with pyoderma gangrenosum on his shoulder. The patient suffered from chronic venous insufficiency, diabetes and arterial hypertension. We started a systemic glucocorticoid therapy in which the patient demonstrated a quick and good response. The wound healed within 2months. After 7months, the same patient developed new pyoderma gangrenosum on both groins after catheterisation. We restarted the systemic glucocorticoid therapywhich had to be combinedwith cyclosporine A because of the prolonged course over more than 3months. Both wounds healed completely. Again 3months later, he developed a new pyoderma gangrenosum pectoral on the left hip and left shoulder, so that we restarted a systemic therapy with glucocorticoids and cyclosporine A. Due to the continuing size progress, we decided to switch to ustekinumab therapy but the patient did not show response to therapy and developed new lesions under his breast and clavicle (Figure 1). Because of the untypical clinical course, we decided to reexamine the patient. He underwent an abdominal and thoracic CT scans, which showed a renal carcinoma on the left kidney. The systemic treatments were stopped and a radical nephrectomy