Medicolegal aspects of error in pathology.
OBJECTIVE: To discuss the various ways error is defined in surgical pathology. To identify errors in pathology practice identified by an analysis of pathology malpractice claims. DESIGN: Three hundred seventy-eight pathology malpractice claims were reviewed. Nuisance claims and autopsy claims were excluded; 335 pathology claims remained and were analyzed to identify repetitive patterns of specimen type and diagnostic category. SETTING: All pathology malpractice claims reported to The Doctors Company of Napa, Calif, between 1998 and 2003. RESULTS: Fifty-seven percent of malpractice claims involved just 5 categories of specimen type and/or diagnostic error, namely, breast specimens, melanoma, cervical Papanicolaou tests, gynecologic specimens, and system (operational) errors. Sixty-three percent of claims involved failure to diagnose cancer, resulting in delay in diagnosis or inappropriate treatment. CONCLUSION: A false-negative diagnosis of melanoma was the single most common reason for filing a malpractice claim against a pathologist. Nearly one third involved melanoma misdiagnosed as Spitz nevus, "dysplastic" nevus, spindle cell squamous carcinoma, atypical fibroxanthoma, and dermatofibroma. While breast biopsy claims were a close second to melanoma, when combined with breast fine-needle aspiration and breast frozen section claims, breast specimens were the most common cause of pathology malpractice claims. Cervical Papanicolaou test claims were third in frequency behind melanoma and breast; 98% involved false-negative Papanicolaou tests. Forty-two percent of gynecologic surgical pathology claims involved misdiagnosed ovarian tumors, and 85% of these were false-negative diagnoses of malignancy. The most common cause of system errors was specimen "mix-ups" involving breast or prostate needle biopsies.