Medical Case Reports

Gastrointestinal Stromal Tumour of Anal Canal; A Case Report and Literature Review

Gastrointestinal Stromal Tumour (GIST) is a mesenchymal neoplasm that expresses KIT or CD117 receptor. It constitutes 1% of all gastrointestinal tumours. Common anatomical distribution includes stomach (50-60%) and small bowel (30-40%). Less common location reported includes colon (7%), and esophagus (1%). GIST of anal canal is rare and only a few cases have been reported in literature. Surgical treatment is preferred in resectable tumours. Selective tyrosine kinase inhibitors is the current standard of care in non-resectable cases. Radiation therapy has been applied to non-resectable GIST with variable outcomes. We present a case of 50-year old male with perianal swelling and bleeding of 1 month duration. Colonoscopy showed circumferential growth 0.5cm from anal verge. Histopathology is consistent with mesenchymal tumour positive for CD117, CD34, and Caldesmon. Computer Tomography (CT) scan showed local infiltration to presacral space, mesorectal fascia and poor plane with prostate gland and levator ani. No distant metastasis noted. He underwent local radiotherapy and given Imitinib and is currently awaiting reassessment for response to therapy pending further intervention.

Muhammad Ezzra Shah Rahman Shah 1*, Nur Zawani Z1, Husna Syakirah1, Wan Mokhzani1, Zaidi
Zakaria1, Syed Hassan1