Abstract
BACKGROUND: The pathological type of simple squamous carcinoma in colorectal malignancies is rare. Simple squamous cell carcinoma of the colorectum occurs most frequently in the rectum. The clinicopathological features and biological behaviors of squamous colorectal carcinoma are unclear, and its prognosis may be worse than that of simple adenocarcinoma. Studies on squamous colorectal cancer are currently limited to case reports, and there is no standard treatment protocol. Therefore, more case reports are required to fully understand squamous colorectal cancer. CASE SUMMARY: We reported the case of a 56-year-old woman who complained of constipation for 2 years. Colonoscopy revealed a sigmoid colon tumor, and the pathological result of colonoscopy was squamous carcinoma. After completing the relevant assessment, the patient was clinically diagnosed with cT4aN0M0, stage IIB, and surgery was performed. Based on postoperative pathological results, the patient was diagnosed with pT4bN0M0, stage IIC. Six cycles of adjuvant chemotherapy were administered after surgery. Liver metastasis and abdominal wall mass were found more than 1 mo after the end of the last chemotherapy session. Targeted local treatment was not performed because the liver had multiple metastases, but I(125) particle implantation of the abdominal wall mass was performed. Two cycles of first-line chemotherapy were administered after the surgery. The patient underwent 14 mo of treatment and eventually died from the tumor. CONCLUSION: Squamous carcinoma of sigmoid colon is a rare tumor with unclear pathogenesis. Its clinicopathological diagnosis should be paid close attention.