*Digestive Disease Center, Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon, Korea.
†Department of Pathology, Soonchunhyang University College of Medicine, Bucheon, Korea.
Colorectal cancer (CRC) is one of the most common cancers in the world. CRCs usually progress from adenomatous polyps, and the morphological and genetic progression of CRCs in an adenoma-adenocarcinoma sequence has been well described.1,2 A hyperplastic polyp (HP) is the most common histological type found among colorectal polyps, but they have been considered to have no malignant potential. However, recent studies have demonstrated that some HPs can develop into CRCs, especially in patients diagnosed with hyperplastic polyposis syndrome (HPS).3,4 Recent studies have proposed that HPs arising in HPS progress toward adenocarcinoma through a "serrated neoplastic pathway" and that a B type Raf kinase (
A 34-year-old young woman visited our hospital for a general health check. She had no family or personal history of colorectal carcinoma or other bowel diseases. However, she underwent a fine-needle aspiration biopsy (FNAB) for incidentally discovered thyroid nodules 2 months previous. The FNAB of these nodules demonstrated bland-looking follicular cells. Her complete blood count showed no abnormal findings, and other laboratory tests and thyroid function tests were within the normal range. She underwent an esophagogastroduodenoscopy and colonoscopy. At the esophagogastroduodenoscopy, numerous 0.2 to 0.7-cm-sized polyps were seen in the body and antrum of the stomach (Fig. 1). However, no lesions were observed in the bulb or secondary portion of the duodenum. During the colonoscopy, numerous 0.2 to 1.0-cm-sized polyps were also observed in the transverse colon, sigmoid colon and rectum. The polyps were mainly distributed on the sigmoid colon and rectum. An upper gastrointestinal series showed no lesions in the small bowel. We removed 48 and 70 polyps from the stomach and colorectum, respectively. A histological examination of the resected polyps revealed HPs (Fig. 2). Based on our findings, the patient was diagnosed with coexisting HPS and gastric hyperplastic polyposis. We performed a
Sporadic HPs are of a benign nature and are usually small in size, multiply, increase with old age, and are mainly distributed in the sigmoid colon and rectum. However, CRCs arising in colorectal HPs or serrated adenomas (SAs), especially in patients diagnosed with HPS have been reported.10-14 Additionally, recent studies proposed the HP-SA-carcinoma sequence as an alternative pathway for colorectal carcinogenesis.4,15,16 HPS is an uncommon syndrome characterized by a diverse range of polyp types including multiple, large HPs and smaller numbers of SAs, traditional adenomas, and admixed hyperplastic/adenomatous polyps in the colon and rectum. In the World Health Organization (WHO) HPS diagnostic criteria, Burt and Jass17 defined HPS as at least five histologically diagnosed HPs occurring proximal to the sigmoid colon and of which more than two are greater than 1 cm in diameter, or more than 30 HPs in the whole colon and rectum, or any number of HPs proximal to the sigmoid colon in an individual who has a first-degree relative diagnosed with HPS. In such patients, polyps are usually sessile and 1-7 mm in diameter, but larger and/or pedunculated HPs may also be observed. Some patients had adenomas or CRCs.18-20 HPs of HPS progress to CRCs through the serrated pathway and a