An unusual cervical carcinoma showing exception to epitheliotropism of human papillomavirus

Human papillomaviruses (HPV) infect epithelial tissues but have not been previously detected within mesenchymal cells. During a systematic investigation of FIGO stage Ib cervical cancers with colorimetric in situ hybridization, we detected HPV 16 DNA within the stromal compartment of an unusual undifferentiated carcinoma. The mesenchymal nature of the HPV-containing cells was confirmed by immunohistochemistry and electron microscopy. No viral particles were identified. Sequencing the majority of the HPV 16 genome identified few changes from the revised reference clone; all previously reported in other HPV 16 variants. These viral changes are unlikely to explain the exceptional mesenchymal localization of the HPV 16 DNA in this case.