Turcot Syndrome: A Case Report in an Unsuspected Setting
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- Chung, H.J., Oh, S.T., Kim, J.G. et al. J Gastrointest Surg (2012) 16: 411. doi:10.1007/s11605-011-1698-0
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Turcot syndrome (TS) is a rare hereditary disorder named after Dr. Jacques Turcot who first reported it in 1959.1 The primary clinical feature of TS is the concurrent presence of multiple colorectal adenomas or carcinomas and primary tumors of the central nervous system. The mode of transmission for TS may be either autosomal dominant or autosomal recessive.2,3 To date, TS has been subdivided clinically and genetically into two subtypes.4,5 TS type 1 has mutations in one of the mismatch repair (MMR) genes (MSH2, MSH6, MLH1, PMS1, and PMS2) that are usually found in hereditary nonpolyposis colorectal cancer (HNPCC) and is associated with glioblastoma. TS type 2 has a germline mutation of the adenomatous polyposis coli (APC) gene that is usually found in familial adenomatous polyposis and is associated with anaplastic astrocytoma, ependymoma, or medulloblastoma.4,5
We report the case of a TS type 1 female patient who had survived exceptionally long with glioblastoma multiforme (GBM) and who had experienced an unusually long gap between the initial diagnosis of GBM and colon cancer.
Since Dr. Turcot reported the first TS case, fewer than 200 patients have been identified with the syndrome, although many cases have not documented genetic analyses.6 TS type 2 consists of two thirds of all TS cases7 and most of TS type 2 patients harbor the germline APC gene mutation.8 TS type 1 account one third of TS cases and shows MMR gene mutations, commonly involving MSH2, MLH1.4,5 For CNS tumor, TS type 1 shows GBM and TS type 2 consists of mainly medulloblastoma. Our patient showed GBM and colon cancer with a mutation of the MLH1 gene (1721T>C). The patient case described herein was consistent with TS type 1.
Seventy percent of patients with Turcot syndrome present with intestinal cancer and develop the CNS manifestations within 5 years; the mean age range of disease onset is in the second and third decades.5,9 However, if brain tumors appear first, colonic polyps tend to become symptomatic within 1 year.10–12 Our patient had an unusual 12-year gap between the initial diagnosis of GBM and developing colon cancers. This length of survival following the diagnosis of GBM is exceptional. In a review of 100 patients with TS, the average survival of GBM patients was estimated at 27 months post diagnosis, much longer than the typical 12 months in sporadic GBM patients.5 In the previous study by Hamilton et al., the length of survival for four patients with glioblastoma was over 3 years.4 Among these patients, two developed GBM first. Recently, Sarin et al. reported on a TS type-2 patient who had an unusual 22-year gap between the initial diagnosis of medulloblastoma and colon cancer.13 Although the reported cases of TS-associated brain tumor have often been associated with enhanced survival time, however the reason remains in question.
In our case, the patient had two large lower abdominal masses that were suspected bilateral multicystic borderline ovarian cystadenoma or cystadenocarcinoma by MRI. During operation, gynecologist found sigmoid colon cancer and referred to colorectal surgeon. We checked the entire abdominal cavity, including the colon and the rectum; no other lesions were found. However, there was the possibility that cancers of the ascending colon and hepatic flexure were ignored because a mechanical bowel preparation had not been done. Those cancers were found on colonoscopic examination 1 month after the operation. It is not clear whether or not they existed at the first operation time. This case demonstrates the limitation of imaging studies and the importance of colonoscopic examination in diagnosing large pelvic masses. If there is no result of colonoscopic examination, we should consider doing a perioperative colonoscopic examination.
In conclusion, our case demonstrates that colonoscopic examination is important in the evaluation of pelvic masses to rule out a colonic neoplasia. In this case, the gynecologist should have suspected TS and performed a preoperative colonoscopy. Suspicion and awareness of Turcot syndrome enable physicians to diagnose and to treat it properly. When a colorectal tumor is encountered without the use of colonoscopy, one should perform postoperative follow-up with colonoscopy in the short term. If possible, intraoperative colonoscopic examination may help with proper treatment of the patient.