Analysis of the Misdiagnosis of a Case of Rectal Lymphoid Polyp: a Case Report

Abstract Background: Lymphoid polyps are rare benign lesions, mainly in the intestinal tract. But misdiagnosis always happen, because it is difficult to distinguish lymphoid polyp and lymphoma and laterally spreading tumour (LST) solely relying on endoscopic examination. Generally speaking, pathology can help us make a correct diagnosis, but in few cases advanced methods is necessary for diagnosis, such as immunohistochemistry and gene rearrangement. Case presentation: A 56-year-old female patient was admitted to the ward for endoscopic submucosal dissection (ESD) treatment. She was diagnosed with laterally spreading tumour (LST) in another hospital. Before ESD treatment, we performed a colonoscopy examination on the patient. The result pointed towards rectal lymphoma and did not support the diagnosis of LSTs of the rectum, so we did not perform ESD. Because of the possibility of missed diagnosis and misdiagnosis of common endoscopic biopsy, we performed endoscopic mucosal resection (EMR) biopsy. The results of postoperative pathology, immunohistochemistry and gene rearrangement supported the diagnosis of lymphoid polyps. Conclusions: The diagnosis of lymphoid polyps always depends on endoscopic examination and pathology. If necessary, advanced methods such as immunohistochemistry and gene rearrangement may be helpful.