METASTATIC ANAL CANAL SQUAMOUS CELL CARCINOMA (SCC) TO THE LIVER: CASE REPORT

Case Presentation A 43-year-old female patient presented with complaints of painful defecation, tenesmus, and narrow stools. She had no comorbidities or relevant family history. Physical examination revealed a vegetative, ulcerated lesion in the right anorectal ring. Colonoscopy identified a neoplastic lesion in the distal rectum and anal canal, measuring 4 cm, and histopathology confirmed poorly differentiated squamous cell carcinoma (SCC). Staging included abdominal and thoracic CT scans, which showed no metastases, while pelvic MRI revealed thickening of the distal rectum, mesorectal fat invasion, and enlarged lymph nodes. The patient was referred for treatment with the Nigro protocol (chemoradiation). Post-treatment MRI revealed hepatic lesions and rectal involvement beyond the muscularis propria. Physical examination identified a hardened lesion 3 cm from the anal verge. Biopsy confirmed SCC with atypia suggesting HPV infection. A PET scan showed uptake in the anal canal and liver lesion.

Restaging Confirmed persistent/recurrent SCC with liver metastasis. Due to insufficient response to chemotherapy, abdominoperineal resection of the rectum and left hepatectomy were performed. Histopathology revealed SCC infiltrating up to the vaginal mucosa, with clear margins, and 1 of 17 lymph nodes affected (T4aN1M1). The patient is currently under outpatient follow-up with imaging control.

Discussion SCC of the anal canal is rare, accounting for less than 2% of gastrointestinal tract cancers, and strongly associated with HPV. Up to 30% of cases may be asymptomatic, with rectal bleeding as the most common symptom in 45% of cases. Other symptoms include pain, tenesmus, and incontinence. Prevention and screening involve HPV vaccination and diagnostic tools such as high-resolution anoscopy and anal Pap smears, although no standardized screening program exists. Staging should assess the primary tumor's spread and locoregional disease, utilizing pelvic MRI, transanal ultrasound, and abdominal/thoracic CT scans. Data on chemotherapy for metastatic SCC cases with complete resection is limited. Following the failure of the standard treatment, a multidisciplinary and individualized approach was adopted.

Conclusion Until the 1980s, abdominoperineal resection was the standard treatment, associated with high morbidity and permanent stoma rates. The Nigro protocol (1974) demonstrated efficacy with combined chemoradiation and has become the current standard of care. Metastatic disease is generally managed with systemic chemotherapy, but metastasectomy may improve overall survival in selected cases.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025