We present a case of a 46-year-old man who developed malignant transformation of a neurenteric cyst felt to be completely removed 14 years previously. He re-presented with non-specific symptoms and hydrocephalus, and subsequent evidence of a complex lesion surrounding the lower brain stem and upper cervical cord. Histologically the original lesion was a benign neurenteric cyst, whereas the recurrent lesion showed a well differentiated adenocarcinoma. This is only the second case reported in the literature.