A laterally spreading tumor (LST) of the rectum with lymphatic metastasis: a case report and literature review

Background: Colorectal cancer (CRC), as one of the most common gastrointestinal malignancies (10.0% of total cancer cases), is also the second leading cause of cancer death (9.4% of the total cancer deaths). Morphologically, early colorectal tumors could be divided into 3 groups: protruded tumors, depress tumors and laterally spreading tumors. Laterally spreading tumors (LSTs) are defined as lesions >10mm in diameter and extending laterally along the luminal wall, by first proposed by Kudo, a Japanese scholar, in 1993. In recent years, the incidence of LSTs has significantly increased. However, LSTs in the rectum with lymphatic metastasis are rarely report. Case presentation: Our team reported a 69-year-old man with abdominal pain, diarrhea and a rectal LST 7 cm in diameter. The rectal lesion was initially diagnosed as a tubulovillous adenoma and some areas show high-grade intraepithelial neoplasia. A therapeutic strategy of laparoscopic assisted radical resection of low rectal cancer (Dixon, D3, TME) was applied. The surgeries and postoperative procedure went smoothly. Conclusions: : This is a rare and clinically significant case that demonstrates the possibility of lymph node metastasis in early intramucosal carcinoma and focuses on the diagnostic and therapeutic schedule of early colorectal cancerous lesions.