Intestinal occlusion caused by Rosai–Dorfman disease mimicking colonic diverticulitis

Rosai–Dorfman disease (RDD) involves the gastrointestinal tract only in exceptional cases, and this very unusual site of presentation can confuse the pathologist. We present a case of RDD manifesting as an intestinal occlusion caused by colonic diverticulitis. The patient was a 79-year-old man with myelodysplasia, who presented with fever, abdominal pain, and constipation. Colonoscopy revealed sigmoiditis and diverticulosis. Microscopic study of the sigmoid colon surgical specimen showed the histological and immunological features of RDD. No human DNA of herpesvirus types 6 and 8 (HHV6/HHV8), Epstein–Barr virus (EBV), and cytomegalovirus (CMV) was detected in tissue by polymerase chain reaction. Electron microscopic study revealed no microbes or viral particles. Widespread nodal and extranodal RDD occurred, and the patient died 2 y after initial surgery. The etiology of RDD is still under debate. We discuss the association of RDD with hematological disorders.