<prompt> Which type of malignancy is found in anorectal fistulaSq. cell CaTransitional cell CaAdeno CaColumnar Ca  <response>: Although rare, the incidence of anal squamous cell carcinoma SCC is rising, with a direct association with HPV infection, AIN and immunosuppression. Thus, high-risk groups are those infected with HPV especially subtypes 16, 18, 31 or 33 .Advanced tumours may cause faecal incontinence by invasion of the sphincters and, in women, anterior extension may result in anovaginal fistulation Ref: Bailey Love;s Sho Practice of Surgery,E25,Page-1269 