Adenomatous transformation in a giant solitary Peutz-Jeghers-type hamartomatous polyp.

Solitary Peutz-Jeghers-type polyp is a rare hamartomatous polyp without associated mucocutaneous pigmentation or a family history of Peutz-Jeghers Syndrome. It is usually encountered in the small intestine, but rarely involves the rectum. A 27-year-old previously healthy female patient presented with a two-month history of rectal bleeding. The patient had neither mucocutaneous pigmentation nor a family history of gastro-intestinal polyposis. Endoscopic examination revealed a solitary lobular polypoid lesion in the lower rectum. The polyp was sessile and measured 15 cm in diameter. As histological examination of the biopsy specimen was suggestive of adenoma, endoscopic polypectomy was performed. Histologically, this polyp had an arborizing muscular network originating from the muscularis mucosa, and was covered by well organized mucosa with several foci of dysplastic glands. The final pathological diagnosis was solitary Peutz-Jeghers type hamartomatous polyp with adenomatous transformation.