Simultaneous Colonic Adenocarcinoma and Medulloblastoma in a 12-Year-Old with Biallelic Deletions in PMS2

We describe a 12-year-old girl, simultaneously presenting with colonic adenocarcinoma and medulloblastoma from bialleic deletions in the mismatch repair gene PMS2. Her distinctive physical and clinical findings are characteristic of constitutional mismatch repair deficiency syndrome. Earlier recognition of such findings may permit better screening and more effective treatment.