Constitutional Mismatch Repair-Deficiency SyndromeAllred, Rebecca J. MD; Samowitz, Wade MDAJSP: Reviews & Reports: March/April 2013 - Volume 18 - Issue 2 - p 79–80 doi: 10.1097/PCR.0b013e31828c33a5 Case Reviews Abstract Author Information Constitutional mismatch repair-deficiency is a rare cause of early onset cancers, including those commonly associated with Lynch syndrome. We report a case of 2 siblings who presented with multiple adenomatous polyps in their 20s and discuss the differential diagnosis and pathogenesis of several hereditary polyposis syndromes. From the Department of Pathology, University of Utah, Salt Lake City, UT. Reprints: Rebecca J. Allred, MD, Huntsman Cancer Hospital, Attn: Pathology, 1950 Circle of Hope, RM N3105, Salt Lake City, UT 84112. E-mail: firstname.lastname@example.org. The authors have no funding or conflicts to declare. © 2013 Lippincott Williams & Wilkins, Inc.