Acute lymphoblastic lymphoma/leukaemia in a dysplastic rectal polyp

Abstract

Constitutional mismatch repair deficiency (CMMRD) syndrome is a recently defined syndrome caused by biallelic inheritance of mutated PMS2, MLH1, MSH2 or MSH6 genes that predisposes those affected to developing malignancies of the central nervous system, gastrointestinal tract and haematological system in childhood and adolescence. Outcomes are generally poor, and risk of synchronous and metachronous disease is high. As a prelude to learning about CMMRD, we present this case where we diagnosed acute lymphoblastic leukaemia/lymphoma in a tubular adenoma from a 9-year-old female.