Institutional review of outside cytology materials: a retrospective analysis of two institutions' experiences.

Discrepancy rates between original and review histopathologic diagnoses have been well-studied, and range as high as 30% in some studies. While the sensitivity and specificity rates for a variety of cytologic specimens are well-known, few data exist as to the discrepancy rates associated with in-house, second-opinion reviews of outside material. We studied the 2-yr experience of two university-based medical centers' reviews of outside cytology materials. A total of 146 cases underwent second-opinion review. The majority were fine-needle aspiration specimens obtained from the breast, thyroid, lung, and hematobiliary system. Nine cases were cervical vaginal specimens, 19 were bronchial brushes, washings, or lavage specimens, 13 were pleural fluid specimens, 5 were bile duct brushings, and the remainder were exfoliative cytologies, including those from the cerebrospinal fluid, urine, and pelvis. In all, 24 disagreements were encountered, 11 of which were considered major in that a significant change in therapy occurred due to an alteration in diagnosis, while 13 were considered minor in that a different diagnosis or subclassification was given by the consultant pathologist, but this diagnostic change did not significantly alter therapy. The overall diagnosis disagreement rate of 16% is similar to the diagnostic discrepancy rate encountered in second-opinion reviews of surgical pathology specimens. The 8% major discrepancy rate is slightly higher than that seen in similar studies of surgical pathology material.