Case ReportSquamous Cell Carcinoma of the Anal Verge with Sigmoid Colon Metastasis
Introduction
The incidence of anal cancer has been rising by about 2% per year.1 Nearly 90% of anal squamous cell carcinoma (SCCA) is associated with high-risk human papillomavirus (HPV) infection, predominantly HPV types 16 and 18.2 Risk factors for developing SCCA include multiple sexual partners, receptive anal sex, and a history of other HPV-associated cancers. Other risk factors include human immunodeficiency virus (HIV) infection, smoking, immunosuppression, and female sex.3,4 SCCA is usually identified with localized disease, although it can metastasize. In this instance, we report a case of SCCA with an unusual clinical course that was discovered in a patient without the typical risk factors.
Section snippets
Case Presentation
A 57-year-old man with a history of hypertension and alcohol use disorder in remission presented with 3 months of bright red blood per rectum, tenesmus, and fatigue. His most recent colonoscopy from 3 years prior was unremarkable. He had no history of smoking and was HIV negative. His digital rectal exam at the time of presentation was concerning for a mass in the anal canal. He underwent a colonoscopy that showed a large, ulcerated, non-obstructing mass in his distal rectum originating below
Discussion
Squamous cell carcinoma of the anus is a rare cancer in the general population, although it is more often seen in HIV-positive patients, men who have sex with men, and patients with immunosuppression. Approximately 90% of SCCA cases are attributed to infection with high-risk HPV subtypes 16 and 18, paralleling the higher rates of infection in the aforementioned groups.6 Other risk factors include smoking history, increased numbers of sexual partners, sexually transmitted infections, or
Conclusion
This is a unique case of a young patient with a large, metastatic squamous cell carcinoma of the anal canal with primary tumor involving the base of the prostate with metastasis to his sigmoid colon. This case emphasizes the importance of addressing the primary tumor with chemoradiation but also indicates the necessity to consider surgical resection of surgically resectable metastatic disease within a timely interval to prevent further potential complications, as in this case of fistula
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