The risk of malignant change developing in the hamartomatous polyps in Peutz-Jeghers syndrome is widely held to be negligible. However an association with tumours of the upper gastro-intestinal tract, ovary and other diverse multiple neoplasms is now recognized. Previously reported cases of malignant change in Peutz--Jeghers polyps may represent 'pseudoinvasion' and we report such a case. This was associated with carcinomas of the bile ducts, left tonsil and a papillary adenoma of the pancreatic duct. It lends further support to the view that there may be a genetic predisposition to the development of neoplasms in this condition. Pathologists and clinicians must be aware of this entity of 'pseudoinvasion' in order to avoid unnecessarily radical surgery in Peutz-Jeghers syndrome.