Solitary Peutz-Jeghers type hamartomatous polyps in the duodenum are not always associated with a low risk of cancer: two case reports

Introduction A hamartomatous polyp without associated mucocutaneous pigmentation or a family history of Peutz-Jeghers Syndrome is diagnosed as a solitary Peutz-Jeghers type hamartomatous polyp. As compared with Peutz-Jeghers Syndrome, Peutz-Jeghers type hamartomatous polyps are diagnosed with a lower risk of cancer and are regarded as a different disorder. Case presentation In case one, we describe an 84-year-old Japanese man with a 14 mm duodenal polyp. Endoscopic mucosal resection was performed and histological examination showed findings suggestive of a hamartomatous polyp with a focus of well-differentiated adenocarcinoma. In case two, we describe a 76-year-old Japanese man who had been treated for prostate, rectal and lung cancer. Upper gastrointestinal endoscopy revealed a duodenal polyp measuring 15 mm in diameter. Endoscopic mucosal resection was performed, and histological examination showed findings suggestive of a hamartomatous polyp. Liver and thyroid cancers were found after the endoscopic treatment. Conclusion Although duodenal solitary hamartomatous polyps are associated with a lower risk of cancer, four patients, including our cases, have been diagnosed with cancerous polyps. Patients with duodenal solitary hamartomatous polyps should be treated by endoscopic or surgical resection and need whole-body screening.

A hamartomatous polyp without associated mucocutaneous pigmentation or a family history of PJS is diagnosed as a solitary Peutz-Jeghers type hamartomatous polyp [4]. As compared with PJS, Peutz-Jeghers type hamartomatous polyps are diagnosed with a lower risk of cancer [5] and have been regarded as a different disorder from PJS.
We report two cases with a solitary Peutz-Jeghers type hamartomatous polyp treated by endoscopic mucosal resection.

Case Presentations
Case 1 is an 84-year-old Japanese man with previous medical history of hypertension, chronic hepatitis C infection, idiopathic thrombocytopenic purpura and colon polyps (tubular adenoma and tubulovillous adenoma). He had no mucocutaneous pigmentation or family history of PJS. An upper gastrointestinal endoscopy revealed a lobular polyp measuring 14 mm in diameter, in the superior duodenal angle ( Figure 1). Endoscopic mucosal resection was performed without complication and histological examination showed findings suggestive of a hamartomatous polyp-branching bundles of smooth muscle fibers covered by hyperplastic duodenal mucosa-with a focus of well-differentiated adenocarcinoma ( Figure 2). A colonoscopy and smallintestinal follow-through showed no other polyps.
Case 2 is a 76-year-old Japanese man who had been treated for prostate, rectal and lung cancer, with no mucocutaneous pigmentation or family history of PJS. An upper gastrointestinal endoscopy revealed a duodenal polyp measuring 15 mm in diameter in the second part of his duodenum ( Figure 3). Endoscopic mucosal resection was performed, and histological examination showed findings suggestive of a hamartomatous polyp (Figure 4). A colonoscopy and smallintestinal follow-through showed no other polyps. After the endoscopic treatment, concomitant liver and thyroid cancers were found.

Discussion
As compared with PJS, Peutz-Jeghers type hamartomatous polyps are diagnosed at a more advanced age, in the absence of mutation of the STK11/LKB-1 gene, and without familial history and mucocutaneous pigmentation [5].
Previous reports showed that polyps due to PJS had 3-6% of neoplastic change, such as adenomas or carcinomas [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. A search of case reports on the MEDLINE database up to July 2010, using the terms "hamartomatous polyp" and "duodenum", and of reference lists of published articles (including our cases), showed 27 patients with a solitary Peutz-Jeghers type hamartomatous polyp in the duodenum (     The most serious problem in PJS is an increased risk of cancer in the gastrointestinal tract. The occurrence of cancer in the gastrointestinal tract has been reported in 20-25% of patients with PJS, and a risk of cancer in other organs has been also reported, including the ovary, breast, bladder, pancreas and thyroid [2,[19][20][21][22].
To the best of our knowledge, there have been no previous reports of patients with solitary Peutz-Jeghers type hamartomatous polyps presenting with malignancy in other organs. This is one of the reasons that solitary Peutz-Jeghers type hamartomatous polyps have been considered as a separate clinical entity from PJS. However, Case 2 in our report had duplicated malignancy in six organs. An overlap between solitary Peutz-Jeghers type hamartomatous polyps and PJS may need to be reexamined.
Our two cases were diagnosed in patients with an advanced age similar to previous reports, but they differ in the malignant alteration of a hamartomatous polyp and concomitant other cancers. Patients with duodenal Peutz-Jeghers type hamartomatous polyps should undergo colonoscopy and whole-body screening; duodenal solitary Peutz-Jeghers type hamartomatous polyps should preferably be treated by endoscopic or surgical resection.

Conclusions
We report two cases of duodenal solitary Peutz-Jeghers type hamartomatous polyp. Case 1 was a hamartomatous polyp with a focus of well-differentiated adenocarcinoma, and Case 2 was a hamartomatous polyp with  five cancers in other organs. We advise that patients with duodenal solitary Peutz-Jeghers type hamartomatous polyps should preferably be treated with endscopic or surgical resection and whole-body screening.

Consent
Written informed consent was obtained from both patients for publication of these case reports and any accompanying images. Copies of the written consent are available for review by the Editor-in-Chief of this journal.