Peutz-Jeghers syndrome with metastasizing carcinoma arising from a jejunal hamartoma

The association of Peutz-Jeghers (P-J) syndrome and gastrointestinal carcinoma is well documented, but an unequivocal histologic demonstration that malignancy may originate in a hamartomatous polyp has been very rarely given. A patient with the P-J syndome is described, in whom a definite intestinal adenocarcinoma with metastases to omentum and celiac lymph nodes was shown to originate in a jejunal hamartoma. Evidence that malignancy was derived from hamartomatous structures was given by the following observations: (a) Adenocarcinoma was intimately intricated with smooth muscle bands, and well-defined transitional zone of malignant cells could be observed in several glands of the degenerated P-J polyp; and (b) close to malignant areas, glands of this polyp exhibited a less-differentiated epithelium, but were still intermixed with nonstriated muscle bundles, which strongly suggest dedifferentiation of hamartomatous structures.