ECP 2023 Abstracts

S254 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Results: The tumour was heterogeneous with the following compo- nents: (1) Carcinomatous with Pax-8/ WT1 positive serous carcinoma and squamous cell carcinoma, with frequent squamous elements showing cytoplasmic clearing conferring a foetal appearance, (2) Sar- comatous, with undifferentiated spindle and pleomorphic cells with heterologous elements (chondrosarcoma and MyoD1 positive rhab- domyosarcoma), (3) Sheets and nests of undifferentiated immature neuroepithelium (EMA negative, synaptophysin, chromogranin, CD56 strong positive, neurofilament/NeuN focal positive), (4) Yolk-sac-like glandular elements with features suggestive of endodermal sinus tubules, with basal and apical vacuolation (glypican patchy positive, SALL4, AFP focal positive). NGS showed loss of SMARCA4 , chro- mosome 12p amplification (with secondary amplification of several oncogenes in the same region), and TP53 mutation. Conclusion: The novel finding of SMARCA4 loss in this ovarian TCS is in concordance with the SMARCA4 inactivation recently discovered as the dominant genetic event in sinonasal TCSs. This finding points towards a somatic derivation. Some cases of gynaecological tract TCS may belong to the group of SMARCA4 -deficient tumours. The study of additional cases is necessary to confirm the incidence of this finding. E-PS-10-010 Intrauterine adhesions: correlations between clinical, immunohis- tochemical, molecular and atomic profile R. Balan*, L. Toma, R. Socolov, N. Simionescu, D. Socolov, B. Toma, T.A. Balan, S.E. Giu ș că, I.D. Căruntu *"Grigore T. Popa" University of Medicine and Pharmacy, Romania Background & objectives: Intrauterine adhesions (IUA) can be asymp- tomatic, leading to overlooked diagnosis, or symptomatic, accompanied by menstrual abnormalities, infertility, and pelvic pain. Due to serious impairment of reproductive function, we aimed to assess the clinical, immunohistochemical, molecular, and atomic profile of IUA. Methods: Our retrospective study included two groups of fertile aged women. The first one comprised 58 patients with IUA, treated during 2016-2022 by hysteroscopy with adhesiolysis, presenting hypo/amenor- rhea, infertility, and pelvic pain. The control group involved 25 women with other pathologies hysteroscopically diagnosed. Biopsy tissue samples were histopathological and immunohistochemical examined, prepared for RNA extraction, and atomic force microscope (AFM) evaluation. Results: The histopathological examination of the first group revealed a secretory endometrium, with stromal fibrosis and focal chronic inflammatory infiltrate. The immunohistochemical and mRNA expres- sions of SUSD2, CD31, NG2, PDGFR beta, CD 146 and Nestin, in the damaged endometrium and control group, were assessed. The mRNA expression levels of all six studied markers were less elevated in the damaged endometrium group versus control group. The immunohisto- chemical expression was higher in the first group versus control group. The atomic force microscope (AFM) evaluation revealed differences between markers. The AFM detected the morphological and topo- graphical changes, which demonstrates the capture of measurements of various parameters in different stages of intrauterine adhesions. Conclusion: IUA represents a challenging disease, although it is often neglected. The reserved prognosis of the disease is related to the limited therapeutic results and the complex endometrial environment. Exploring IUA through innovative techniques contributes to a deeper understanding of the pathogenic mechanisms of endometrial regeneration and repair in women with IUA. The AFM analysis of the IUA tissue compared to the normal endometrium represents the first study in the literature to date. E-PS-10-011 Clinicopathological and immunohistochemical correlations of abdominal wall endometriosis after caesarean section T.A. Balan*, R. Balan, I.D. Căruntu, I. Păvăleanu, L. Lozneanu, S.E. Giu ș că, C. Amalinei *"Grigore T. Popa" University of Medicine and Pharmacy, Romania Background & objectives: Abdominal wall endometriosis after the caesarean section (AWECS) is a rare entity, with sometimes latent development. As AWECS can mimick other entities or may undergo malignant transformation, we aim to assess the clinicopathological and immunohistochemical features of this endometriosis type. Methods: Our retrospective study reviewed 16 cases of abdominal wall endometriosis, related to caesarean section, surgically removed and diagnosed by routine histological methods, supplemented with additional immunohistochemical techniques (ER, PR, CD10, CD45, S100), within the Pathology Department of the Clinical Hospital of Obstetrics and Gynaecology "Elena Doamna" from Iasi, Romania, for a period of 10 years (2012-2022). Results: The clinical and ultrasound diagnosis were made on the exist- ence of a tumour mass at the level of the post-caesarean scar, with cyclical variability in size and pain. Surgical treatment consisted of wide local excision with clear margins. The histopathological diagnosis revealed endometrial glands and/or stroma in dermis and subcutaneous tissues, accompanied by a mixed inflammatory infiltrate within or adja- cent to endometriotic stroma, highlighted also by immunohistochemi- cal assessment, CD10 revealing also possible endometrial stem cells. In our study, 4 patients (25%) presented a cutaneous endometriotic nodule, and 11 patients (75%) presented subcutaneous endometriosis. All cases presented positive immunoexpression of the studied markers. The clinico-pathological agreement for AWECS diagnosis was 68.75%. Conclusion: AWECS should be considered in the case of a reproduc- tive age women with a tumour mass at the level of a caesarean section scar, accompanied by cyclical pain. The histopathological examination, sometimes supported by immunohistochemical evaluation, represents the gold standard diagnosis for AWECS and for excluding a possi- ble malignancy. An extensive panel of immunohistochemical markers could demonstrate the existence of endometrial stem cells in endo- metriotic foci, thus contributing to the completion of the pathogenic theories of the mechanisms involved in AWECS. E-PS-10-012 Extensive accumulation of hemostatic agent reminants through pelvic peritoneal surfaces mimicking mucin: a diagnostic pitfall H. Berber*, A.T. Bol Serttürk, D. Enneli, C. Cansız Ersoz *Ankara University Medical School, Pathology Department, Turkey Background & objectives: Oxidized regenerated cellulose(ORC) is a hemostatic agent commonly used in surgical interventions. ORC-par- ticles remained through the peritoneal surfaces may pose a diagnostic challenge during the histopathological examination of the specimens, in case of being unawareness, as in the present case. Methods: A 43-year-old female patient was admitted to the emergency department of our hospital, with the complaint of right lower quadrant pain. Imaging studies (abdominal ultrasound and computerized tomog- raphy) revealed a haemorrhagic cyst, 7 cm in long diameter, in the right ovary, and as the possibility of ovarian torsion can’t be ruled out, the patient underwent right salpingoopherectomy. Results: Macroscopic examination revealed multiple cysts in the ovary, with the largest haemorrhagic one, 7cm in long diameter. These were incompatible with haemorrhagic corpus luteum cyst and follicle cysts, histologically. The striking feature was the accumulation of extensive, basophilic material in the fimbria, ovarian cortex, mesovarium, along the pelvic peritoneal surfaces, reminiscent of mucin, at first glance, and dense histiocytic proliferation, some mimicking mucinophages includ- ing this material within their cytoplasm. Paler, pinky staining of this material by PAS/mucicarmine dyes removed the suspicion of mucin. Then the clinical history of the patient was questioned and learned that the patient had previously undergone cholecystectomy and ORC was used for hemostasis.