2007 Winter Meeting - London - The Pathological Society of Great ...

P25An Interesting Case of Indigestion{P} R Arora, P PichmanWest Herts Hospital NHS Trust, Northwood, London, United KingdomPancreatic heterotopia or aberrant pancreatic tissue in not an uncommoncondition in the antrun and pyloric canal. Most of these are howeverunsymptomatic. Some which become symptomatic require surgicalresection.They can mimic other upper gastrointestinal pathologiesendoscopically and histopathologically.We present an interesting case of distal gastrectomy performed forsymptoms of indigestion and pyloric obstruction in a 70 year old male.Macroscopically there was a 12mm firm area at the antrum which on histologyshowed islands of varying sizes of glandular structures within the muscularispropira which were interspersed with smooth muscle and fibrous tissue.Occasional foci of heterotopic pancreatic tissue including acinar cells andneuroendoocrine islet-like cells were seen. These apprearences are ofadenomyoma or myoepithelial hamartoma which is thought to be a congenitalabnormality due to separation of fragments of pancreatic tissue from the mainmass of the pancreas during rotation of the forgut.P26Evaluation of Genomic Instability in Sporadic ColorectalCancers: Array-Comparative Genomic HybridisationOutperforms Flow Cytometric Analysis{P} G Poulogiannis 1 ,KIchimura 1 , NG Miller 1 , IM Frayling 2 ,RG Morris 3 , DJ Harrison 3 , VP Collins 1 , A Ibrahim 1 , AH Wyllie 1 ,MJ Arends 11 University of Cambridge, Pathology Department, Cambridge, UnitedKingdom, 2 University Hospital of Wales, Institute of Medical Genetics,Cardiff, United Kingdom, 3 University of Edinburgh, PathologyDepartment, Edinburgh, United KingdomColorectal cancers (CRCs) show at least two patterns of genomic instability:chromosomal instability resulting in aneuploidy, and microsatellite instability(usually occurring in near-diploid CRCs), with inactivation of the DNAmismatch repair (MMR) pathway, and sometimes both patterns or neither. Inthis study, we evaluated chromosomal instability in >100 sporadic CRCs using1Mb array-comparative genomic hybridisation (aCGH) to assess DNA copynumber alterations of the whole genome with arrays of 2904 cloned DNAinserts (mean clone size 152kb) spaced on average 0.97 Mb apart. Thequantitative assessment of DNA copy number changes by aCGH identifiedmany genomic abnormalities ranging from copy number variations of entirechromosomes and chromosomal arms to small micro-deletions and micro-gainsof chromosomal subregions. The overall DNA content of these CRCs was alsoevaluated by the quantitative assessment of propidium iodide labelled tumournuclei by flow cytometry (FCM). Comparison of FCM DNA histograms withaCGH analyses showed that a significant proportion of tumours with a neardiploidDNA content by FCM exhibited >1000 DNA copy number changes byaCGH indicating widespread chromosomal instability. This discrepancy islargely due to tumours displaying approximately equivalent numbers of DNAgains and losses resulting in an overall near-diploid DNA content. Most (>85%)MMR defective CRCs showed near-diploidy with few DNA breakpoints byaCGH. Furthermore, we developed a computational method to correlate aCGHdetectedDNA copy number changes in CRCs with published changes in theexpression levels of genes localised to the relevant chromosomal regions inorder to identify novel putative oncogenes, such as LIVIN that showed copynumber gains in ~70% of CRCs. We conclude that flow cytometric analysis ofDNA ploidy underestimates chromosomal instability in CRCs, whereas aCGHprovides a more accurate evaluation of chromosomal instability and canidentify novel putative cancer-related genes.P27Poster withdrawnP28The Predictive Value for Adenocarcinoma of HGPIN andAtypical Small Acinar Proliferation (ASAP) in ProstateNeedle BiopsiesL Hatsell, {P} N MayerUniversity Hospitals of Leicester NHS Trust, Leicester, United KingdomBackground and Aims: High grade prostatic intraepithelial neoplasia(HGPIN) is characterised by architecturally benign prostatic glands lined bycytologically atypical cells. Atypical small acinar proliferation (ASAP), ratherthan being a specific diagnostic entity, is a term used to describe a focus ofglands which are suspicious for adenocarcinoma but for a variety of reasons fallbelow the threshold for a definite cancer diagnosis. In this retrospective auditof prostate needle biopsies, we compared our own diagnostic rates of HGPINand ASAP and their predictive values for a subsequent diagnosis ofadenocarcinoma against published standards. Methods: We identified 162biopsies with an initial diagnosis of HGPIN and/or ASAP and determined howmany of these had adenocarcinoma on re-biopsy. We compared this with acontrol group with a benign first biopsy. Results: In 2004 and 2005, HGPINaccounted for 6.9% and 5.8% of all prostate biopsies, respectively. Our‘suspicious rate’ (ASAP and ASAP/HGPIN) was 2.6% in 2004 and 2.3% in2005. The predictive value for adenocarcinoma in the HGPIN group was 15%which was similar to the control group of 13% (P=0.746). The predictive valuefor ASAP was 24% (P=0.286) and combined ASAP/HGPIN 33% (P=0.150).Conclusion: Our diagnostic rates for HGPIN and ASAP are withinrecommended guidelines. The predictive value for adenocarcinoma in theisolated HGPIN group is virtually the same as in the control group who had abenign first biopsy. The predictive value of ASAP and ASAP/HGPIN is higher(although failing to reach statistical significance).These results are in keepingwith recent published series and suggest a diagnosis of isolated HGPIN doesnot justify immediate re-biopsy whereas ASAP or combined ASAP/HGPINprobably does.34 Winter Meeting (191 st ) 3–5 January 2007 Scientific Programme