Keratoacanthoma as a complication of arterial puncture for blood gases

In July 1979, a 72-year-old white woman presented to the Bernalillo County Medical Center Emergency Department with complaints of shortness of breath and wheezing. She had been asthmatic since childhood. Current management included bronchodilator therapy and continuous low flow oxygen. An apparently curative left radical nephrectomy had been performed in 1978 for renal cell carcinoma. Her evaluation in the emergency room included multiple attempts at right radial artery puncture for blood gases. The arterial blood gases were obtained only after repeated efforts by several individuals. The patient was discharged from the emergency room after receiving subcutaneous terbutaline and intravenous aminophylline. Approximately one week later, she noticed a swelling on her right wrist at the site of the punctures. Over the ensuing three weeks, the lesion doubled in size and became painful. In chest clinic, one month after emergency room visit, we found a 1 cm by 1 cm raised erythematous tender nodule on the right wrist overlying the radial artery pulse. We did not hear a bruit, the lesion did not feel fluctuant, and attempts to aspirate fluid were unsuccessful. Because we thought the lesion represented local infection, we began oral antibiotic therapy. The lesion was unchanged after 1 1/2 weeks of therapy and was excised. Pathologic examination showed a well-defined cutaneous nodule with histology diagnostic of a keratocanthoma. The patient developed a recurrence of the tumor at the excision site a few weeks later and required a wide excision, also under local anesthesia. She has since remained clinically free of recurrent tumor.