Evaluation of the accuracy of frozen section in different anatomical sites

ABSTRACT INTRODUCTION: Frozen section is recommended in several situations to: establish the nature of a lesion; establish the presence of a lesion; confirm the presence of a benign lesion; confirm that sufficient tissue is present for diagnosis; establish the grade of the lesion; determine the organ of origin and determine the adequacy of margins. OBJECTIVES: To evaluate the accuracy of frozen section biopsy in multiple organs and analyze possible factors in discrepancy. METHODS: A retrospective study was carried out during a five-year period at a teaching hospital of Recife, Pernambuco, Brazil. The diagnoses of frozen section were compared with results obtained in the permanent section and classified as concordant or discordant. The discordant cases were reviewed by a pathologist and subdivided into false positives and false negatives. Possible reasons for discrepancy were indicated. RESULTS: A total of 1.226 specimens were analyzed, of which 1.181 (96.33%) were concordant and 45 (3.67%) were discordant. After the review of the discordant cases, 39 remained, six (15.4%) were false positives and 33 (84.6%) were false negatives. The tissue that had most false-positive results was mammary sentinel lymph node (3/1.2%), whereas ovarian showed most false negative outcomes with 17 specimens (51.51% of all false negatives). The possible reasons for discrepancy were sampling error, misunderstanding and complexity of the diagnosis. CONCLUSION: The frozen section accuracy of 96.3% found in our study is similar to specialized literature and does not seem to depend on the tissue analyzed.

摘要：
引言：冰冻切片（Frozen section）在多种临床场景中被推荐使用，其应用目的包括：明确病变性质、确认病变存在、证实良性病变存在、确认获取的组织量足以支持诊断、确定病变分级、明确病变起源器官以及判断切缘是否充足。
目的：评估多器官冰冻切片活检的诊断准确性，并分析诊断不符的潜在影响因素。
方法：本研究为回顾性研究，于巴西伯南布哥州累西腓的一所教学医院开展，研究周期为五年。将冰冻切片诊断结果与常规石蜡切片（permanent section）结果进行比对，分为相符（concordant）与不符（discordant）两类。由病理医师对不符病例进行复阅，并将其细分为假阳性（false positives）与假阴性（false negatives），同时明确诊断不符的潜在原因。
结果：本研究共分析1226例标本，其中1181例（96.33%）诊断相符，45例（3.67%）诊断不符。对不符病例复阅后，有效纳入39例，其中假阳性6例（15.4%），假阴性33例（84.6%）。假阳性病例最多的组织类型为乳腺前哨淋巴结（3例，占比1.2%），而假阴性病例最多的组织类型为卵巢组织，共17例（占所有假阴性例数的51.51%）。本研究中诊断不符的潜在原因为取材误差、认知偏差及病变诊断复杂性。
结论：本研究中冰冻切片诊断准确率为96.3%，与专业文献报道结果相近，且该准确率似乎不受所分析组织类型的影响。