How many histological levels should be examined from tissue blocks originating in cone biopsy and large loop excision of the transformation zone specimens of cervix?

AIMS To establish the value of examining additional histological levels in cone biopsy and large loop excision of the transformation zone (LLETZ) specimens of cervix. METHODS Three deeper levels were examined from 200 consecutive cone biopsy and LLETZ specimens reported by a single pathologist. RESULTS Examination of the first deeper level resulted in cervical intraepithelial neoplasia (CIN) being identified for the first time in five cases and in CIN1 being upgraded in five more. Invasive cancer was discovered in two cases that had shown high grade CIN initially. CONCLUSION Examination of a single further level appears to be sufficient in those patients in whom a specimen is compromised because epithelium including the squamocolumnar junction is missing, or if there is a discrepancy between the histological findings and the preceding colposcopic or cytological history. If invasive disease is suspected on the basis of the cytological, colposcopic, or histological features, one or preferably two further levels should be examined.