Abstract
BACKGROUND: The gastrointestinal tract is a well-known extranodal site of lymphoma. B-cell lymphoma is the most common type, while T-cell lymphoma is uncommon. Primary gastrointestinal lymphoma mainly occurs in the stomach and small intestine, and the colon is less frequently involved, especially in females. CASE SUMMARY: A 45-year-old woman was admitted to our hospital for physical examination. Gastroenteroscopy revealed a visible pedunculated polyp in the transverse colon, for which endoscopic submucosal dissection (ESD) was performed. Pathology suggested highly active proliferation of T lymphocytes with atypical hyperplasia. CONCLUSION: A middle-aged female patient was found to have colonic T-cell lymphoma by endoscopy. The lesion was successfully removed by ESD, and the surgical margin was negative. It is essential to raise awareness of colonic T-cell lymphoma and choose the appropriate treatment.