This case illustrates a T3 N0 anal tumor. Biopsy confirmed that it represents squamous cell carcinoma of the anal canal. Remember that, as opposed to rectal cancer, anal tumor staging is mostly based on size and extension, rather than wall invasion.

The systemic spread of anal SCC is uncommon, reported to occur in 5-8% at initial diagnosis, usually seen involving the retroperitoneal para-aortic lymph nodes, liver, lungs, and skin. The abnormal intensity in the skeleton seen in this case is non-specific and, although metastatic disease to bones is unlikely, a bone scan was recommended to rule out metastasis.