Introduction. Primary squamous cell carcinoma (SCC) of the colon is a rare histological subtype of CRC with poor prognosis. It most frequently occurs in the right colon, and least commonly in the sigm..
Introduction. Primary squamous cell carcinoma (SCC) of the colon is a rare histological subtype of CRC with poor prognosis. It most frequently occurs in the right colon, and least commonly in the sigmoid colon. Similar CRC symptoms no matter the subtype can range from asymptomatic to rectal bleeding, abdominal pain, change in bowel habits, and weight loss. Here, we describe a case of primary basaloid SCC of the sigmoid colon. Case description. A 71-year-old female with no significant past medical history presented with guaiac-positive stools, underwent a colonoscopy revealing an ulcerated mass in the left colon. Histopathology and immunohistochemical results at this point favored a SCC. A subsequent PET scan was negative. Given the lack of evidence of a metastatic lesion on PET scan alongside the pathology results, a primary SCC of the colon was favored. Discussion. Although the pathogenesis of SCC of the colon is not fully understood, one theory includes damage to the colonic mucosa by chronic inflammatory conditions (IBD) or infection (HPV), that may result in squamous cell metaplasia of the colorectal epithelium. To diagnose a primary colorectal SCC there should be no indication of SCC in any other organ that could lead to colon metastasis, and no squamous-lined fistula tract should be present. Careful investigation of rectum and cervix to exclude SCC of anal origin with proximal extension, and cervical HPV related squamous cell lesions should be evaluated.
