The authors report a case of basaloid carcinoma involving the anus and rectum of 
a 57-year-old woman. Microscopically, the tumor showed unusual morphologic 
features strongly resembling a spiradenocylindroma because it consisted, in most 
parts, of basaloid cell nodules arranged in a jigsaw-puzzle fashion containing 
or surrounded by eosinophilic basal membrane material; in addition, there were 
intratumoral lymphocytes. The overlying squamous epithelium manifested 
dysplastic changes compatible with in situ squamous carcinoma that gradually 
became invasive and blended with basaloid cell islands; additionally, there were 
koilocytes in the squamous epithelium. A molecular biology study identified 
HPV-16 in the lesional tissue. Analysis of the CYLD gene did not prove any 
mutation.