We describe a patient with a severe juvenile polyposis phenotype, due to a de 
novo deletion of chromosome 10q22.3-q24.1. He was initially diagnosed with 
Juvenile polyposis syndrome (JPS) at age four after presenting with hematochezia 
due to multiple colonic juvenile polyps. He then re-presented at 23 years with 
recurrent hematochezia from juvenile polyps in his ileoanal pouch. He is one of 
the earliest reported cases of JPS associated with a large deletion of 
chromosome 10. Since his initial diagnosis of JPS further studies have confirmed 
an association between JPS and mutations in BMPR1A in chromosome band 10q23.2, 
which is in close proximity to PTEN. Mutations in PTEN cause Cowden syndrome 
(CS) and other PTEN hamartoma tumor syndromes. Due to the chromosome 10 deletion 
involving contiguous portions of BMPR1A and PTEN in our patient, he may be at 
risk for CS associated cancers and features, in addition to the polyps 
associated with JPS. This case presents new challenges in developing appropriate 
surveillance algorithms to account for the risks associated with each syndrome 
and highlights the importance of longitudinal follow-up and transitional care 
between pediatric and adult gastroenterology for patients with hereditary 
polyposis syndromes.