ECP 2023 Abstracts

S208 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Methods: To examine haemorrhoidectomy samples and identify the rare presentation of hidradenoma papilliferum in the anal region, uti- lizing H&E staining and immunohistochemistry (IHC) for hormonal receptor and epithelial membrane antigen (EMA). Results: Histopathological examination of the haemorrhoidectomy samples revealed an incidental hidradenoma papilliferum in the pos- terolateral right resection. The tumour appeared as a well-circum- scribed, cystic-papillary lesion with benign characteristics. Cystic and papillary structures consisted of multiple stalks with vascular- ized fibroconnective tissue, covered by epithelium exhibiting apocrine decapitation secretion. The resection margins were tumour-free, and surrounding tissues displayed mixed haemorrhoids with congestive changes. Immunohistochemical staining was performed on the tumour sections to confirm the diagnosis of hidradenoma papilliferum. Oestrogen receptor expression was detected in the tumour cells, confirming the diagnosis. Additionally, (EMA) staining highlighted the cellular mem- branes, further supporting the diagnosis of hidradenoma papilliferum. Conclusion: This case report underscores the rare occurrence of hidradenoma papilliferum in the anal region, discovered incidentally during a haemorrhoidectomy. The diagnosis was confirmed through histopathological examination. Further studies and case reports are needed to better understand the aetiology, risk factors, and optimal management strategies for hidradenoma papilliferum in this unusual location. Clinicians should be aware of such rare presentations to facili- tate accurate diagnosis and appropriate treatment. E-PS-06-060 Use of routine special stains for gastric and oesophageal biopsies I. Mallek*, O. Belkacem, B. Bouchabou, M. Mbarek, A. Lahmar, D. Bacha, S. Ben Slama *Monji Slim La Marsa, Tunisia Background & objectives: Special stains are performed systemically, in some laboratories, for the diagnosis of H. pylori and intestinal meta- plasia (IM). The aim of this study was to evaluate the contribution of these stains in gastric and/or oesophageal biopsies. Methods: This retrospective study included consecutive gastric and oesophageal over a six-month period. During this period, we received 209 biopsies from 139 patients. The H. pylori and IM were initially visualized on H&E-stained slides, In a second step, we analysed the corresponding Giemsa stained. Then, we examined the corresponding slides stained with PAS and the Alcian Blue (AB). Results: The results of the H&E and Giemsa were concordant in 173 biopsies (82.8% of all biopsies) with kappa = 0.58: The two tests were not concordant in 36 biopsies (17,2%). IM was present in 11 H&E sec- tions (5,3% in all biopsies sites) and absent in 198 cases (94,7%). The AB has therefore made no diagnostic gain since all negative biopsies on H&E stain were also negative on AB stain. Comparing the iden- tification of IM on PAS and H&E stains, concordance was in 99.5% (207 biopsies). Conclusion: Routine special stains for detection of H. pylori and IM are not required for most gastric and/or oesophageal biopsies. The best positive predictor is the presence of neutrophils, combined with chronic inflammation. If H. pylori eradication treatment has failed, then the presence of neutrophils is a sensitive marker of that failure and if organ- isms are not seen on H&E, then special stain or immunohistochemical stain should be performed. E-PS-06-061 Clinicopathological features of colorectal cancer in patients younger than 40 years of age in Northern Tunisia I. Mallek*, S. Ben Slama, B. Bouchabou, M. Mbarek, M. Hajri, H. Mestiri, A. Lahmar, D. Bacha *Monji Slim La Marsa, Tunisia Background & objectives: Colorectal carcinoma (CRC) in patients younger than 40 years is rare but incidence is increasing. The objective of this study was to describe demographics, clinico-pathologic and therapeu- tic management and to evaluate prognosis factors in this young population. Methods: It was a retrospective study including with CRC in patients under the age of 40. Results: 40 cases were under the age of 40 among 428 patients with CRC (9,34%) (Sex ratio M/F =0.8, average age = 33.6 years). Family history of cancer was present in 20%, and predisposing factors were present in 25% of the patients. The cancer was rectal in 55% of cases and colic in 45%. It was adenocarcinoma (not other specification) in 75% of cases with MSI-H phenotype in 17,5% of cases. The tumours were classified as stage II in 40% of cases and stage III in 47.5% of cases. The overall 5-year survival rate was 27%. Patients without Inflammatory Bowl Diseases history have significant increase in survival (p<0.05). Conclusion: Young patients with colorectal cancer with predispos- ing factors have poorer prognosis in a population in Northern Tunisia. E-PS-06-062 Predictive factors for histological response to neo-adjuvant treat- ment in rectal cancers I. Mallek*, S. Ben Slama, B. Bouchabou, M. Mbarek, M. Hajri, H. Mestiri, A. Lahmar, D. Bacha *Monji Slim La Marsa, Tunisia Background & objectives: Histological response is the goal of neo- adjuvant treatment of locally advanced rectal cancer. Results of various studies focused on pathological predictive response factors are discord- ant. The aim of this study was to search factors of histological response to neo-adjuvant treatment. Methods: Retrospective study involving 44 patients with locally advanced rectal adenocarcinoma who received neo-adjuvant radio- therapy or radiochemotherapy. The prognostic factors studied were clinical (age and sex), radiological (tumour size and parietal inva- sion) and histological (histological grade, vascular and nerve inva- sion) features. Complete histological response was defined by Bate- man’s tumour grade m-RCRG 1 and the absence of lymph node metastases. Results: A complete histological response was observed in 25% of cases (n = 11). In multivariate analysis, age> 60 years (OR: 1.14 and p = 0.028), male sex (OR: 21 and p = 0.045) and radiological wall invasion exceeding the subserosa (OR: 11 , 5 and p = 0.008) were significantly associated with the histological response. In contrast, none of the 3 histo- logical factors tested were correlated with this response’s intensity. Conclusion: Age, gender, and pre-therapeutic parietal invasion could be used to select «good» and «poor» responders to neo-adjuvant treat- ment in locally advanced rectal cancers. E-PS-06-063 Intestinal spirochaetosis: review of cases diagnosed in a third level hospital J. Martínez Castillón*, S. Vicente Arregui, E. Del Valle Sánchez, M.Á. Trigo Cebrián, C. Hörndler Argarate, J.L. Delgado Fernández, N. Mar- tínez Arnau, A. Carilla Sanromán, L. Leon, L. Ollero Domenche *Hospital Universitario Miguel Servet, Spain Background & objectives: Intestinal spirochaetosis is a bacterial growth defined by the colonization of the apical membrane of the colo- rectal mucosa by spirochetes, wich generally do not become invasive. The gold standard for the diagnosis is the detection of microorganisms by histological examination. Methods: A retrospective review was carried out, using the PAT-Win database, of the intestinal biopsies coded with the SNOMED " Spi- rochete", during the period from 2017 to 2023 at the Miguel Servet University Hospital in Zaragoza. Subsequently, the epidemiological