ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Methods: To comparatively assess the staining patterns of these markers across a broad range of different tumour entities, tissue microarrays containing 7711 neoplasms from 117 different tumour types and subtypes was analysed by immunohistochemistry. Results: Positivity for CK20, SATB2, CDH17, and villin was seen in 94.4%, 88.1%, 98.3%, and 96.7% of colorectal, 36.4%, 22.4%, 52.8%, and 72.4% of gastric, 38.3%, 15%, 51.7%, and 65% of oesophageal adenocarcinomas, 49.1%, 20.8%, 69.8%, and 66% of adenocarcinomas of the ampulla of Vater, 19.4%, 1.4%, 40.3%, and 54.9% of pancreatic ductal adenocarcinomas, 8.7%, 2.2%, 2.2%, and 23.9% of hepatocellular carcinomas, and in 5.5%, 10.1%, 12.8%, and 12.8% of pulmonary adenocarcinomas. A positivity of ≥3 (or all 4) markers occurred in 96.2% (83.2%) of colorectal, 33.2% (13.3%) of gastric, 23.2% (11.7%) of oesophageal, 8.3% (0%) of ductal pancreatic, 0.9% (0%) of pulmonary adenocarcino- mas, and in 0% (0%) of hepatocellular carcinomas. Conclusion: All individual markers support the distinction of GIT adenocarcinomas from liver and lung cancer while a com- bined analysis of multiple markers may increase diagnostic accu- racy. Characteristic staining patterns also occur in other enti- ties. For example, Villin expression is linked to neuroendocrine neoplasms and yolk sac tumours. CDH17 is often positive in in neuroendocrine neoplasms. CK20 is linked to urothelial neo- plasms and Merkel cell carcinomas. SATB2 occurs in Merkel cell carcinomas, renal cell carcinomas, and several mesenchymal tumour entities. PS-07-043 Nonconventional dysplasia in inflammatory bowel disease asso- ciated colorectal adenocarcinoma: a clinicopathologic study of twenty-four cases T. Dot Gómara, S. Rázquin Lizarraga, T. Labiano Miravalles, G. Aísa Rivera, M.C. Llanos Chavarri, M. Bronte Anaut, I. Sánchez Sánchez, E.A. Sierra Arellano, R. Unciti Ruiz, Á. Panizo Santos* *Navarra University Hospital, Spain Background & objectives: Several types of nonconventional dysplasia have been recently described in inflammatory bowel disease (IBD). However, strict morphologic criteria are lacking, and their clinicopathologic features including potential association with conventional dysplasia and/or colorectal cancer are poorly understood. Methods: A total of 24 IBD-associated CRC (IBD-CRC) colectomy specimens of 22 patients were reviewed. Seven morphologic patterns were recognized: hypermucinous dysplasia, traditional serrated adenoma-like, sessile serrated lesion-like and serrated lesion, not otherwise specified, Paneth cell differentiation and goblet cell deficient dysplasia. Lesions were classified according to the WHO 2019 criteria and literature review. Results: We identified 149 dysplastic lesions and occurred with similar frequency in men and women (n=17 and n=5, respectively), with a mean age of 57 years (range: 34-82) with long history (mean: 9,6 years, range: 2-27) of ulcerative colitis (n=11, 42%) and Crohn’s disease (n=13, 58%). All nonconventional dysplasia types were common (55% of the cases), present as focal or extended, pure or mixed, in peritumoral and remote mucosa. Tumours were more likely to be well-differentiated (43%), left-sited (58%), with mucinous features (33%) and signet-ring cell (12.5%). Many cases were deeply invasive (62% were pT3 or pT4) and 54% had lymph node metastasis. Conclusion: Clinicopathological characteristics of IBD-associated CRC were significantly different from sporadic colorectal adeno- carcinoma. Histopathological findings of nonconventional patterns of dysplasia were common in IBD-CRCs. Most cases had mixed and focal or extended features of all nonconventional dysplasia types. Nonconventional dysplasia occurred with similar frequency in ulcerative colitis and Crohn’s disease. We did not find associa- tion between nonconventional dysplasia type and characteristics of IBD-CRC. PS-07-044 Clinicopathological study of retroperitoneal margin invasion in right radical hemicolectomy with colon cancer M.F. Molina-Centelles*, P. Guerrero Antolino, M. Frasson, I. Rienda Martínez, N. Rausell Fontestad, C. Zac Romero, D. Ramos Soler, E. García-Granero Ximénez, F. Giner Segura *Hospital Universitari i Politècnic La Fe de València, Spain Background & objectives: There is high variability in relapse rate among series (3-14%) after right radical hemicolectomy. Retroperitoneal margin is a well-recognized parameter, frequently forgotten. The objective is to assess the invasion of retroperitoneal margin in pathologic specimens after radical right hemicolectomy. Methods: Prospective histopathologic and clinical analysis of 79 patients who underwent right hemicolectomy (2017-2019). Retro- peritoneal margin was inked and measured macro- and microscopi- cally and was defined as affected when tumour distance was less or equal to 1mm. Association between retroperitoneal margin invasion and other histological and oncological results was analysed. Results: Involvement of retroperitoneal margin was found in 15 cases (18.98%) and was significantly associated with more advanced degrees of dedifferentiation (G2: p=0,017; G3: p=0,037) tumour budding (intermediate grade: p=0.028; high grade: p=0.005), presence of poorly differentiated groups (p=0,039) and perineural invasion signs (p=0,044). The involvement of the ret- roperitoneal margin was associated with a worse overall survival (p=<0.01) and worse overall recurrence (p=<0.01). Conclusion: Retroperitoneal surgical margin resection involvement could be considered an anatomopathological marker of poor prognosis and greater incidence of relapse after oncological right colectomy. Tumours involving this circumferential margin show features of aggressive behaviour such as increased degrees of dedifferentiation, tumour budding, presence of poorly differentiated groups and perineural invasion. A greater number of cases and longer follow-up term are needed to confirm the clinical significance of this parameter. PS-07-045 Haemorrhoidectomy specimens: incidental malignant lesions. An eight-year retrospective study with eleven case reports G.G. Yange Zambrano*, G. Moreno-De-Juan, J.C. Yange-Zam- brano, I. Gallego-Gutierrez, N. González-Ortega, M.d.M. Del- Barrio-Molina, M. Novell-Grau *Hospital Mateu Orfila, Spain Background & objectives: The prevalence of haemorrhoids is estimated at 4.4% (up-to 13-20%). Findings of malignant lesions in haemorrhoidectomy specimens are infrequent. The objective of this study is to be aware of the incidence of malignant lesions found in haemorrhoidectomy-specimens, not clinically suspected. Methods: We carried out an eight-years retrospective study of haemorrhoidectomy specimens collected of the Mateu Orfila Hos- pital (Menorca), Spain. All samples coded as “haemorrhoidec- tomy” and/or “haemorrhoid” between 2013 and 2021, were selected from the Pathology Department database. Clinicopathological and demographic variables were collected from the electronic clinical records. Results: 444 specimens from 246 men and 198 women, were analysed. The mean age was 45 years (range 20-84 years). S102