Koilocytes are a type of 'dysplastic' squamous cell found in potentially precancerous lesions - cervical intraepithelial neoplasia(ex, uterine cervix).They are believed to be changes in squamous cells brought about by human papilloma virus (HPV) infection(not conclusively proven).
Papillomaviruses are well known to be oncogenic (cancer causing) in animals. In humans they are associated with benign squamous tumors (condylomata acuminata,verruca vulgaris,and papillomas) in a number of body sites.
Human papillomavirus (HPV) infection of the esophagus,is being increasingly reported.
Esophageal squamous papillomas (ESPs) have been identified.These are believed to be caused by Human papillomavirus (HPV) infection.The lesions of ESPs show presence of significant numbers of Koilocytes.
In the west, mostly they are seen to occur in the lower third of the esophagus. However, in the japanese (in whom severe reflux disease is rare), they have been reported in the middle third of the esophagus.Curiosly, japanese women(more often younger women around 40 years of age), seem to be affected.
Two etiological factors of ESPs have been proposed...
a) hyper-regenerative response of the esophageal mucosa to mechanical & chemical irritation such as chronic food impaction, alcohol consumption, repeated minor trauma, cigarette smoking, gastroesophageal reflux diseases (GERDs)and previous gastroesophageal surgery.
b) Human papillomavirus (HPV) infection.
There are case reports of mastication of verruca vulgaris associated with esophageal squamous papilloma.
Thus there is emerging evidence to link esophageal cancer to HPV via Esophageal squamous papillomas (ESPs).
If indeed some of the esophageal cancers are found to be linked to HPV, whether these tumors will behave any differently and their prognostic significance is as yet unclear.
MB BS, MS, FRCS(Edinburgh)