ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 infiltration of four lymph nodes. Surrounding mucosa of the stenotic and farther dilated bowel showed multiple extensive areas of IBD- associated high-grade dysplasia separated by foci of non-dysplastic epithelium. In the background of the dysplastic changes there were found seven additional synchronous adenocarcinomas with variable depth of invasion. Predominance of not otherwise specified morphol- ogy was seen with minority of poorly cohesive and signet-ring cell morphology. Conclusion: Immunohistochemistry revealed aberrant p53 expres- sion and loss of e-cadherin staining in neoplastic cells irrespective of the morphological type. Molecular analysis revealed pathogenic somatic mutations in TP53 and CDKN2A genes. Hereby presented case with advanced adenocarcinoma of small bowel underscores the difficulty of surveillance and preventive strategy of small bowel IBD associated neoplasia. Presence of extensive preneoplastic lesion and multifocality of the neoplasia also points out the possible effect of field cancerization of small bowel mucosa in the setting of IBD. Funding: Supported by the project BBMRI-CZ LM2018125 E-PS-06-006 Extra-appendiceal goblet cell adenocarcinoma: a new entity or an old companion in a new location? I. Franin*, A. Ibukić, D. Brletić, D. Tomas, A. Demirović *Department of Pathology and Cytology “Ljudevit Jurak”, Sestre milosrdnice University Hospital Centre, Zagreb, Croatia Background & objectives: According to the current WHO classifi- cation, goblet cell adenocarcinoma is a rare appendiceal amphicrine tumour containing goblet-like mucinous cells with variable numbers of endocrine and Paneth-like cells. We present a case of a goblet cell adenocarcinoma of the ascending colon. Methods: A 66-year-old man was admitted to an external institu- tion for colon tumour examination. CT scan confirmed an ascend- ing colon neoplasm, but enlarged mesenteric and retroperitoneal lymph nodes were also present raising suspicion of lymphoma. A biopsy ruled out lymphoma and diagnosis of adenocarcinoma was established. The patient was transferred to our hospital for surgery and right sided hemicolectomy was performed. Results: Gross examination revealed an ulcerated tumour measuring 5 cm with infiltration of muscular wall as well as extensive infiltration of the surrounding adipose tissue and serosal perforation. Histologic examination showed a tumour composed of goblet-like cells with small, compressed nuclei with intracytoplasmic mucin and cuboidal epithelial cells with mitotic activity and focal hyperchromasia. Tumour cells were arranged in an organoid pattern. Appendix was free of tumour. Alcian PAS stain highlighted the intracytoplasmic mucin. Immunohistochemical staining for cytokeratin AE1/AE3 and synaptophysin showed a diffuse positive reaction. These findings were consistent with the diagnosis of goblet cell adenocarcinoma. Conclusion: Several previously published cases show that goblet cell adenocarcinoma can also occur in other parts of the gastro- intestinal tract. In colon, it can easily be mistaken for signet ring cell carcinoma. Recent studies have shown that extra-appendiceal goblet cell adenocarcinoma is a distinct morphological, immuno- histochemical, immunological and transcriptomic entity. Further studies should compare its pathological, molecular and clinical characteristics with appendiceal goblet cell adenocarcinoma and possibly reclassify it as a new type of amphicrine tumour not lim- ited to the appendix. E-PS-06-008 Clinicopathological features of a rare subtype of gastric neoplasm D. Raduta*, L. Nichita, M. Cioplea, L. Sticlaru, E. Ignat, A. Vilaia, O. Stefan, G. Tudor, C. Popp *Colentina Clinical Hospital, Romania Background & objectives: Gastric carcinoma (GC), the third most common cause of cancer-related mortality, includes various subtypes, one of them being GC with lymphoid stroma, comprising between 1-7% of cases. The aim of this study is to investigate the clinicopathological features of GCLS. Methods: We report the case of an 82year-old male investigated for an episode of massive upper gastrointestinal bleeding and important weight loss in another medical centre. The endoscopic examination revealed a gastric tumour localized on the lesser cur- vature. After being transferred in our hospital and further investiga- tions, the patient underwent total gastrectomy with omentectomy, esophago-jejunal anastomosis and regional lymphadenectomy. Results: The macroscopic examination of the specimen revealed an ulcero-infiltrative lesion measuring 4.5x4x2.3 cm, infiltrating the whole gastric wall, without perforating the serosal layer and plenty whitish and firm consistency lymphatic nodes located in the fatty tissue nearby the tumour. On microscopic exam, we found a poorly-differentiated malignant epithelial proliferation with few glandular structures, small trabeculae and nests of epithelial cells embedded in a dense lymphoid infiltrate reminiscent of lymphoid tissue. Lympho- vascular invasion or peri-neural growth it is not detected. We examined 24 lymphatic nodes, half of which were found with metastatic carcinoma. Conclusion: GCLS is a rare subtype of gastric cancer associated with EBV infection and microsatellite instability. Unlike the com- mon subtype of GC, GCLS rather affects the proximal stomach or the gastric stump. The characteristic microscopic finding of GCLS is peritumoral and tumour-infiltrating lymphocytes, but medullary carcinoma is also described in colorectal or breast localization. Patients with GCLS have better survival rates than those non- GCLS, so it’s important to recognize this subtype of GC for pre- dicting the patient’s prognosis and particular treatments. E-PS-06-009 Incidence of dysplasia in Barrett’s oesophagus L. Mikhaleva*, K. Maslenkina, S. Gusniev, V. Olesya, Z. Gioeva *A.P. Avtsyn Research Institute of Human Morphology, Russia Background & objectives: The definition of Barrett’s oesophagus is debatable. While most cases of esophageal adenocarcinoma develop at background of intestinal metaplasia (IM), molecular findings suggest non-IM as ancestor clone of cancer. Our aim was to compare dysplasia incidence in IM and non-IM. Methods: Biopsy was performed in 142 patients with segment of metaplasia in distal oesophagus ranged from C0M1 to C15M15. Biopsy specimens were fixed in 10% neutral buffered formalin and stained with haematoxylin-eosin and combined PASD/ Alcian Blue. Immunohistochemical evaluation with Muc2 was performed in dubious cases to identify true goblet cells. Dysplasia was confirmed by 2 pathologists experienced in gastrointestinal pathology. Results: Difficulties in establishing metaplasia type because of so called pseudo-goblet cells occurred in 25 of 142 patients (17.6%), among them 23 cases (92%) appeared to be non-IM after immunostaining with Muc2. IM was detected in 86 patients, S218