Intestinal neuronal dysplasia (IND) is a well-defined entity which raises controversy among authors, described as a congenital malformation of gastrointestinal innervation and caused by dysplastic embryonal development of the enteric nervous system. It is potentially associated with mild and chronic gastrointestinal motility disturbances. IND is rarely reported in adults and especially elderly patients. The present study reports on the case of a 71-year-old man suffering from longstanding idiopathic constipation and who was misdiagnosed for more than 60 years, despite several hospital admissions and a sigmoidectomy in the meantime. On the last admission, the patient presented with megacolon, abdominal pain and X-ray finding of bowel obstruction. Due to massive large bowel dilatation, an exploratory laparotomy failed to reveal any obvious mechanical cause, and a subtotal colectomy and Hartmann's procedure was performed. Bowel continuity was performed 3 months later. Analysis of full-thickness biopsies revealed enlarged myenteric and submucosal neurons as well as an increased number of giant cells and increased acetylcholinesterase activity in the mucosa. The diagnosis of IND was established. The main diagnostic criteria, the underlining pathophysiology and the recommended therapeutic approach of this rare entity are extensively reviewed.