Peculiar Aspects of Gastroenteric Extra Colonic Manifestations of FAP

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Among the possible extra-colonic manifestations are upper gastroenteric lesions, stomach polyps (25-60% of the patients) and duodenal polyps (24-73%) [19-21]. Hyperplastic polyps are commonly observed at a gastric level, whereas at a duodenal level and in the Vater's ampulla we mostly have real adenomas which are also subject to the rule of "adenoma-carcinoma" progression. Therefore, periodic endoscopic surveillance of the upper gastroenteric tract with possible removal of duodenal adenomas is essential.

An issue which is still open to discussion is the evaluation of the Vater's ampulla [22,23]. It is known that FAP involves a higher risk of adenomas and carcinoma of the ampulla, in addition to duodenal polyposis (an estimated incidence around 60% vs. 3% of general population). The risk of developing adenomas and carcinoma of the Vater's ampulla is increased in patients affected with FAP with an incidence ranging from 50-86% considering adenomas, carcinoma In Situ and adenocarcinoma vs. the 2.9 cases per million people of the general population.

Nowadays the gold standard for diagnosis is represented by endoscopic retrograde cholangiopancreatography (ERCP) which allows evaluation of the morphology of the Vater's ampulla. When there is any doubt about the adenomatous localisations it is possible to perform biopsies of the mucosa after an endoscopic sphincterotomy. Alternatively, when sphincterotomy is contraindicated, a brushing cyto-logic exam could be indicated even if this method is not commonly used at present because of the high percentage of false negatives.

Magnetic resonance cholangiopancreatic (MRCP) could substitute for ERCP in diagnosing ampullary neoplasm, since it offers good imaging of the biliary tree and gives information on the dimension, extension and relationship to the nearby vascularisation of the possible tumour. Staging an ascertained papillary expansive lesion is left to endoscopic ultrasound (EUS). The possibility of performing internal sonographic scansions with different wavelengths (5 and 7.5 MHz) allows visualisation of the wall layers (determining dimension and grade of intramural invasion) as well as the nearby structures (with evaluation of the any lymph-node involvement and the presence of distant metastasis). Diagnostic use of EUS is now foreseen: it must be noted that this procedure has a medium level of invasiveness compared to MRCP (zero invasiveness) and ERCP (high inva-siveness with risks of serious complications such as acute pancreatitis).

Bare local resection can be performed in benign adenomas. In this case it is possible to choose between an endoscopic approach and a surgical one. The former is indicated for adenomas with extra-ampullary growth (periampullary area) smaller than 1 cm and not carrying severe dysplasia, even if the risk of recurrence for incomplete removal is 20%. For adenomas larger than 1 cm and for ampullary ones, surgical polypectomy is indicated as well as resection of the papilla of Vater with reconstruction of the pancreatic and biliary duct by means of an eight shaped plastic.

Surgical removal treatment is possible for 75% of the patients with invasive adenocarcinoma and the primary technique is Whipple's pancreatoduodenectomy, with a mortality rate of less than 5%. In a subpopulation with increased probability of ampullary carcinoma, such as FAP patients, early diagnosis (in the preclinical phase or in the benign phase) should be promoted, since these patients represent a small group at high risk of pathology. In addition, precisely due to this exiguity of cases, promotion is not yet a reality, since there is no standard protocol in the literature for the follow-up, selection and timing of diagnostic exams.

To sum up, even though a higher incidence of ampullary neoplasm for FAP patients is well known, no procedure was identified as being sufficiently sensitive for a subgroup of patients more at risk of developing this manifestation. However, it is likely that, just like the correlation between genetics and severity of colorectal disease, the type of genetic alteration plays an important role also in the development of duodenal and ampullary lesions, again in terms of severity of the disease.

It is known that there are genetic mutations associated with an increased risk of superior gastroen-teric polyposis, stomach and duodenum, such as mutations between codon 1445 and 1578, or between 1395 and 1493; but there are still no indications on the association between specific mutations and ampullary neoplasm. These genetic errors are part of the gene tract normally related to the severe form of FAP, as occurred in one of our patients who came under our observation for jaundice. While awaiting the ultimate genetic mapping, this patient underwent endoscopic removal of an ampullary polyp and contemporary total colectomy with IRA. Later, during short-term surveillance, a cancerised polyp was detected for which this patient was converted from IRA to IPAA; this evolution could have been expected according to the genetic finding of a severe mutation. However, in our series of patients there is an entire family of five female individuals with mild mutation presenting duodenal adenomas which are treated endoscopically; still, two of them had to undergo surgery. The mother presented an ampullary-pancreatic tumour that at the time of the operation allowed only palliative derivation, the daughter instead presented a progression of the duodenal polyps to severe dysplasia and the development of ampullary polyps diagnosed with RMN and EUS, which required surgical management by means of wide transduodenal ampullectomy. Considering the possibility that the duodenal lesions could be related to a genetically severe model of FAP as well as a non-severe one; and, as described in the literature, also in an AFAP, it is clear that endoscopic gastro-duodenal surveillance is recommended to prevent the development of gastric and duodenal polyps for all patients regardless of the mutation [24]. At present the need for a follow-up protocol, based on the individual patient's characteristics and disease features, is increasingly pressing so that lesions can be identified in the preclinical phase, when radical treatment is still possible.

As already mentioned, even desmoid tumours are problematic in treating FAP [25, 26]. Intra-abdomi-nal desmoid tumours may significantly affect the choice of surgical treatment or, if they develop during the postoperative stage, they are extremely difficult to treat and results are often unsatisfactory. Abdominal-wall desmoid tumours are less aggressive and easier to treat, and therefore can be entirely removed [27]. In our experience, parietal desmoid tumours appear in four out of five cases after surgery at the site of surgical scarring.

This aspect led us to think that long incisions and trauma on the muscles could support the subsequent development of abdominal-wall desmoids. Regarding this hypothesis, we are evaluating the impact that small scars such as the ones we have with the VDL approach, could have in determining desmoid development. Up to now only one of the patients operated on with the VDL approach has developed a desmoid tumour where the former protection ileostomy was.

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