title: Colorectal Cancer due to Constitutional Mismatch Repair Deficiency Mimicking Neurofibromatosis I.
abstract: Colorectal carcinoma (CRC) is an extremely rare tumor of childhood that can be associated with cancer predisposition syndromes. A patient with CRC related to constitutional mismatch repair deficiency (CMMRD) syndrome with features of neurofibromatosis type 1 (NF-1) is presented here. A 13-year-old boy was admitted for a 4-month history of diarrhea and rectal bleeding. The patient had extensive café au lait spots, freckling, and Lisch nodules. He fulfilled the NF-1 diagnostic criteria. Colonoscopy showed numerous polyps and a colorectal mass lesion, of which a biopsy revealed adenocarcinoma, an uncommon pathology associated with NF-1. High microsatellite instability and homozygous mutation of PMS2 gene in tumor tissue and blood lymphocytes, respectively, confirmed the diagnosis of CMMRD. Unfortunately, because family history related to CMMRD was negative, the parents denied the diagnosis and refused the therapy, and the patient was lost to follow-up. CMMRD is a rare cancer predisposition syndrome with phenotypical features resembling NF-1. The disease may be suspected in the setting of NF-1 features and CRC, high-grade brain tumors, or hematologic malignancies. Lack of family history related to CMMRD may be a major obstacle to convincing parents of the presence of an inherited disease in their progeny.
authors.affiliation: Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey; and.
authors.forename: Nafiye
authors.initials: N
authors.lastname: Urganci
authors.affiliation: Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey; and baharbeker@yahoo.com.
authors.forename: Dildar Bahar
authors.initials: DB
authors.lastname: Genc
authors.affiliation: Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey; and.
authors.forename: Gulsen
authors.initials: G
authors.lastname: Kose
authors.affiliation: Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey.
authors.forename: Zerrin
authors.initials: Z
authors.lastname: Onal
authors.affiliation: Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey; and.
authors.forename: Ozge Ozdemir
authors.initials: OO
authors.lastname: Vidin
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000209:etiology*; D000251:Adenosine Triphosphatases / Q000235:genetics; D000293:Adolescent; D014408:Biomarkers, Tumor / Q000235:genetics; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000235:genetics; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics; D045643:DNA Repair Enzymes / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D003937:Diagnosis, Differential; D006720:Homozygote; D006801:Humans; D008297:Male; D000070976:Mismatch Repair Endonuclease PMS2; D009154:Mutation; D009386:Neoplastic Syndromes, Hereditary / Q000175:diagnosis* / Q000235:genetics; D009456:Neurofibromatosis 1 / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D000251:Adenosine Triphosphatases; C094934:PMS2 protein, human; D000070976:Mismatch Repair Endonuclease PMS2; D045643:DNA Repair Enzymes