Ectopic chromosome around centrosome in metaphase cells as a marker of high-risk human papillomavirus-associated cervical intraepithelial neoplasias

This report describes the appearance of ectopic chromosome around centrosome (ECAC) in metaphase cell nuclei of high-risk HPV-associated cervical neoplasms. ECAC are clearly visible on HE-stained sections as a tiny (approx. 0.7 μ), round, dark structure or an aggregate of filamentous chromosome, often symmetrical at bilateral centrosomes. They appear in CINs from an early stage (CIN I), with the highest incidence in HPV16-associated CIN II-III (75%), and are less common in HPV-related invasive carcinomas (21%) and in lesions associated with high-risk HPV types other than 16. Rates for ECAC-positive nuclei in metaphase preparations (ECAC rate) for each lesion ranged 3.6-30%, the average being 14.5%. ECAC appeared very rarely in CINs associated with intermediate-risk HPVs and was never encountered in HPV6/II-induced condylomas or HPV-unrelated neoplasms in other organs. ECAC may be morphologic evidence of HPV-induced chromosomal instability working as a background mechanism in cervical carcinogenesis and also a useful marker for the histopathologic differentiation of high-risk CINs.