Successful treatment of basaloid squamous cell carcinoma in the rectosigmoid colon: A case report and review of literature.

BACKGROUND Compared with colorectal adenocarcinoma, basaloid squamous cell carcinomas (BSCCs) arising in the colorectum are rare and have very poor prognosis. To date, only nine cases have been reported. Most BSCCs are extensively involved in metastasis to the lymph node, liver, and lung at diagnosis. Despite many clinicians attempting to effectively treat BSCCs, therapeutic consensus has not been established due to lack of information. CASE SUMMARY A 58-year-old woman presented with abdominal pain, diarrhea, fever, and hematochezia. She was referred from a department of gynecology and was diagnosed with a suspicious leiomyosarcoma of the rectum or a pedunculated myoma of the uterus. An exophytic growing mass at the right lateral wall of the rectum with an internal cystic portion and hemorrhage was observed on magnetic resonance imaging. The patient underwent low anterior resection and total hysterectomy with bilateral salphingo-oophorectomy. Histopathological findings revealed a cellular mass with a solid growth pattern and few glandular structures, many foci of intratumoral necrosis, and a palisading pattern. The pathologist diagnosed tumor as a BSCC, and the patient received chemotherapy with fluorouracil/leucovorin without radiotherapy. The patient is currently alive 8 years after the surgery with no manifestations of metastatic colon cancer. CONCLUSION Our case suggest that curative resection and chemotherapy play important roles in improving survival, and radiotherapy may be an option to avoid radiation-associated enteritis.