Abstract
BACKGROUND: Enteropathy-associated T-cell lymphoma (EATL) is a rare invasive lymphoma derived from gastrointestinal epithelial T lymphocytes. EATL involving the whole gastrointestinal tract accompanied with early colon cancer is extremely rare. CASE SUMMARY: We present the case of a 67-year-old man with diarrhea for more than 5 mo whose colonoscopy in another hospital showed multiple colonic polyps, which indicated moderate to severe dysplasia and focal early cancer. Therefore, he was referred to our hospital for further endoscopic treatment. Colonoscopy after admission showed that the mucosa of the terminal ileum and the entire colon were slightly swollen and finely granular. Endoscopic mucosal resection was performed for colonic polyps located in the liver flexure of the colon and descending colon, respectively. Histopathological findings revealed diffuse infiltration of medium-sized lymphoid cells in the colonic mucosa and visible lymphoepithelial lesions. The histopathology of the polyp in the descending colon indicated moderately differentiated adenocarcinoma limited to the mucosa with negative resection margins. Additionally, immunohistochemical analysis showed positive staining for CD7 and CD8. Therefore, we arrived at a diagnosis of EATL with early colon cancer. Subsequently, the patient was transferred to the hematology department for chemotherapy. The patient's diarrhea was not significantly relieved after receiving chemotherapy, and he ultimately died of severe myelosuppression. CONCLUSION: EATL should be considered in unexplained chronic diarrhea. EATL progresses rapidly with a poor prognosis, especially when accompanied with early colon cancer.