[Lynch syndrome I: a case report].
BACKGROUND
Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndromes I and II, accounts for about 5-8% of colorectal cancers. Lynch syndrome I is an autosomal dominant inherited disorder characterized by early onset of colorectal cancer, predominance of proximal and multiple tumors, and microsatellite instability. In order to identify HNPCC, the international "Amsterdam criteria" have been used.


METHODS
The proband was a 40-year-old male who was admitted to hospital with a diagnosis of advanced rectal cancer. Left colectomy was carried out. A histopathologic diagnosis of poorly differentiated adenocarcinoma of clinical stage Dukes C was made. The family talking was done and it was revealed that the proband had five family members (one of first degree relative) with colorectal cancer, and two successive generations affected. All malignancy were diagnosed before 45 years of age. In one family member, metachronous transverse cancer was revealed 12 years after surgery for cecal adenocarcinoma.


CONCLUSIONS
The main molecular cause for HNPCC is constitutional mutation in one of the mismatch repair (MMR) genes that regulate the excision of errors occurring during DNA replication. The most often are mutations of MLH1 and MSH2 genes, and microsatellite instability is present in about 90-95% HNPCC. In this report, we present a case of an HNPCC patient who met the Amsterdam criteria for Lynch syndrome I. Family members that fulfil the Amsterdam criteria should be investigated for mutation in MMR genes. The genetic tests are not routinely available, so colonoscopic screening of all asymptomatic family members older than 25 has been recommended.
Zivković
Vesna
V
Institut za patologiju, Medicinski fakultet Nis.
Katić
Vuka
V
Gligorijević
Jasmina
J
Andelković
Zlatibor
Z
Petrović
Aleksandar
A
Krstić
Miljan
M
D000328:Adult; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D008297:Male