A case of a rare type of cancer: Anal squamous cell carcinoma in a patient without significant risk factors.

INTRODUCTION: Anal carcinoma is a relatively uncommon tumor that accounts for less than 2% of large bowel malignancies and approximately 1-6% of anorectal tumors. Most anal cancers originate in the mucosa between the anorectal junction and the anal verge. Risk factors for anal carcinoma include human papillomavirus (HPV), immunosuppression, older age, female gender, and smoking. Approximately 85% of anal cancers are squamous cell carcinoma, and the pathophysiology is believed to be linked to HPV-related inflammation, leading to dysplasia and progression to cancer.

CASE PRESENTATION: We present the case of a 65-year-old woman who sought medical attention at the emergency department (ED) due to rectal pain and concurrent rectal lesions persisting for the past three months. Before admission, she reported abdominal discomfort and constipation for 2-3 months, during which she took laxatives for relief. Laboratory findings in the ED were significant for anemia and leukocytosis, with all other values within normal limits. Blood tests, including antibodies for HPV and human immunodeficiency virus, were negative. A computed tomography scan of the abdomen and pelvis was largely unremarkable. On physical examination, perianal lesions with heaped-up edges were observed. A punch biopsy was subsequently performed, revealing squamous cell carcinoma (SCC). About three weeks following discharge, after one week of admission to the general medicine ward, the patient started chemoradiation therapy and reported some improvement in her symptoms. Seven weeks later, she was in remission.

DISCUSSION: Squamous cell carcinoma (SCC) of the anus, a rare disease entity, is often a slow and progressive malignancy. The length of time for patients to become symptomatic, in combination with its mimicking clinical presentation to common gastrointestinal tract diseases and its rarity, makes diagnosis challenging. Additionally, a patient lacking traditional risk factors for anal cancer, such as HPV and smoking, may further complicate diagnosis, treatment, and quality of life.

CONCLUSION: This case report emphasizes the pathogenesis and the similarities in clinical presentation of anal cancer to mild diseases, which may lead to a delay in diagnosis. Patients with anal carcinoma often delay seeking medical care, which is anecdotal in relation to the considerable overlap in symptoms of benign diseases such as hemorrhoids. Therefore, patients with "hemorrhoid" complaints, rectal bleeding, or rectal mass should warrant further physical examination and prompt referral to a gastroenterologist or a colorectal surgeon for additional evaluation.