Juvenile polyposis syndrome might be misdiagnosed as familial adenomatous polyposis: a case report and literature review

Abstract

Background Juvenile polyposis syndrome (JPS) is a rare disorder characterized by the presence of multiple juvenile polyps in the gastrointestinal tract, and germline mutations in SMAD4 or BMPR1A. Due to its rarity and complex clinical manifestation, misdiagnosis often occurs in clinical practice. Case presentation A 42-year-old man with multiple pedunculated colorectal polyps and concomitant rectal adenocarcinoma was admitted to our hospital. His mother had died of colon cancer. He was diagnosed with familial adenomatous polyposis (FAP) and underwent total proctocolectomy and ileal pouch anal anastomosis. Two polyps were selected for pathological examination. One polyp had cystically dilated glands with slight dysplasia. The other polyp displayed severe dysplasia and was diagnosed as adenoma. Three years later, his 21-year-old son underwent a colonoscopy that revealed more than 50 pedunculated colorectal juvenile polyps. Both patients harbored a germline pathogenic mutation in BMPR1A. Endoscopic resection of all polyps was attempted but failed. Finally, the son received endoscopic resection of polyps in the rectum and sigmoid colon, and laparoscopic subtotal colectomy. Ten polyps were selected for pathological examination. All were revealed to be typical juvenile polyps, with cystically dilated glands filled with mucus. Thus, the diagnosis of JPS was confirmed in the son. A review of the literatures revealed that patients with JPS can sometimes have adenomatous change. Most polyps in patients with JPS are benign hamartomatous polyps with no dysplasia. A review of 767 colorectal JPS polyps demonstrated that 8.5% of the polyps contained mild to moderate dysplasia, and only 0.3% had severe dysplasia or cancer. It is difficult to differentiate juvenile polyps with dysplasia from adenoma, which could explain why juvenile polyps have been reported to have adenomatous changes in patients with JPS. Therefore, patients with JPS, especially those with concomitant dysplasia and adenocarcinoma, might be easily diagnosed as FAP in clinical practice. Conclusions Juvenile polyp with dysplasia is often diagnosed as adenoma, which might lead to the misdiagnosis of JPS as FAP. The differential diagnosis of JPS versus FAP, should be based on comprehensive evaluation of clinical presentation, endoscopic appearance and genetic investigations; not on the presence or absence of adenoma.

A rare case of a juvenile polyp of patient with Peutz-Jeghers syndrome, complicated with intussusception of the small intestine

“…[9] Furthermore, JPS can be diagnosed only in the absence of other hamartomatous polyposis syndromes, including PJS what excludes our patient as a JPS patient. [10] Polyps of juvenile type are mostly detected in childhood but are very rare in adulthood. [11] Thus, juvenile polyps may often be misdiagnosed as inflammatory polyps.…”

Adenomatous Polyposis Phenotype in Bmpr1a and Smad4 Variant Carriers

“…O'Riordan et al ( 13 ) found that ∼7%–14% of JPS polyps harbored adenomatous changes; however, adenomas as the sole histology of multiple colorectal polyps were not mentioned in any of these patients. Gao et al ( 8 ) reported a family with the BMPR1A variant and multiple juvenile polyps misdiagnosed as multiple adenomas. In our study, polyp histology in all 8 patients, initially reported to be adenomas, was revised by GI pathologists, and the diagnosis of adenoma was confirmed in all cases.…”

Juvenile polyposis syndrome: A case report

“… 14 Therefore, endoscopy studies could help to differentiate FAP (familial adenomatous polyposis) from JPS, as in FAP, most polys have been noted to be sessile. 15 …”

“…Elitsar et al, a review of patients with JPS revealed that 90.5% were stalked and only 9.5% were sessile 14 . Therefore, endoscopy studies could help to differentiate FAP (familial adenomatous polyposis) from JPS, as in FAP, most polys have been noted to be sessile 15 …”