Rationale:Gastrointestinal solitary extramedullary plasmacytoma (EMP) is rare, just occupies about 5% of all EMPs. The most common site is small intestine followed by stomach. The colorectal incidence is much rare.Patient concerns:A 63-year-old female had an episodic pain around the umbilicus for about one week. The hyperemia and edema in the ileocecal mucosa were found in colonoscopy, and the endoscopy could not cross the ileocecal valve. The pathology specimens showed a high index suspicion of plasmacytoma.Diagnoses:The patient was diagnosed with extramedullary plasmacytoma.Interventions:A right hemicolectomy surgery was performed to treat the disease.Outcomes:Post surgery pathologic report showed low grade malignant mucosa associated marginal zone B cell lymphoma.Lessons:We report a case of an extramedullary plasmacytoma in ileocecum with abdominal pain and a review of extramedullary plasmacytoma.