Diagnostic accuracy and appropriateness of care for seborrheic keratoses. A pilot study of an approach to quality assurance for cutaneous surgery In 1985 there were more than 40 million visits for ambulatory surgical procedures in the United States. Although benign cutaneous lesions are among the most frequent conditions to receive surgical treatment in ambulatory settings, their treatment is seldom subject to peer review. In this pilot study we assessed diagnostic accuracy and appropriateness of care using information available from the surgical pathology laboratory. We assessed these two measures of physician performance for 527 seborrheic keratoses removed by 133 clinicians affiliated with four different institutions. Overall, a correct preoperative diagnosis was provided in only 49% of cases. Dermatologists had the highest diagnostic accuracy (61% vs 35% for all other physicians). An appropriate procedure for the actual pathological diagnosis was performed in only 50% of cases. Lesions with a correct preoperative diagnosis were more than eight times more likely to receive appropriate care. Our data suggest that many clinicians fail to note a correct diagnosis of common cutaneous lesions before surgical removal, and many patients are treated with procedures that are more invasive than necessary for the final pathological diagnosis. Because the approach used in this pilot study relies on data already available, it has promise as a low-cost method of monitoring the quality of care of ambulatory surgery. 