ECP 2023 Abstracts

S269 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Conclusion: Primary EGISTs are very rare and occur in the retroperi- toneum, mesentery, omentum, liver, pancreas, spleen, pleura, pelvis, rectovaginal septum and vagina, with morphological and immunophe- totypical features similar to GISTs. EGIST of posterior vaginal wall with liver metastasis is extremely rare. EGIST lymph node metastasis is rare, so lymph node dissection is not recommended. Postoperative adjuvant therapy (Imatinib, chemotherapy, radiotherapy) should be administered and close follow-up is recommended. E-PS-10-063 Riluzole: a neuroprotective drug with possible antineoplastic activ- ity in ovarian cancer? C. Villa*, E. Duranti, C. Venturin, M. Cadamuro, M. Lavitrano *Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy Background & objectives: The glutamate release inhibitor riluzole (RIL) has been shown to reduce the course of amyotrophic lateral sclerosis. Recent research demonstrated that RIL can exert antitumor properties, but no studies have explored its effects on ovarian cancer. Methods: OVCAR5 and OVCAR8 cell lines were treated with different concentrations of RIL (25-1000 μM) for 48 hours. MTT and wound healing assays were performed to investigate the effects of RIL on cell viability and migration, respectively. The expression of proteins linked to these molecular pathways was evaluated by Western blot analysis. Results: No differences in cell viability were found for both cell types after RIL treatment at different concentrations (25, 50, 100, 200, 400, 700 and 1000 μM) for 48 hours. As a result, no changes in cleaved caspase-3 levels were observed. Conversely, wound healing assays revealed that 48h treatment with RIL (50 or 100 μM) significantly reduces cell motility of both OVCAR5 and OVCAR8 to untreated con- trols (p < 0.05). The migration of both cell lines was reduced by more than 30% when compared to the untreated groups. Conclusion: Our preliminary findings suggested that RIL has no effect on cell viability but can significantly slow migration capacity in in the ovarian cancer cell lines OVCAR5 and OVCAR8. However, a more extended research is required to validate our conclusions and to further investigate the molecular targets of RIL and its underlying antitumor mechanisms in ovarian cancer. E-PS-10-064 Luteinized thecoma associated with sclerosing peritonitis in a 13-year-old female: a case report M.N. Villca Huayta*, B. López Martinez- Bernal, A. Van Der Biezen, C. Vieru, M.L. Abascal Camacho, M. Cebollero Presmanes *Hospital General Universitario Gregorio Marañón, Spain Background & objectives: Luteinized thecoma with sclerosing peri- tonitis (LTSP) is an extremely rare lesion. The age range of patients is broad with most cases occurring in the third decade. We describe a case with a view to improving its knowledge and therapeutic management. Methods: We are reporting a case of unilateral ovarian luteinized the- coma with sclerosing peritonitis. A 13-year-old female with abdominal pain that on CT scan showed an abdominal mass dependent on the right ovary, images of micronodular peritoneal dissemination, ascites and bilateral pleural effusion. She had elevated serum tumour marker CA-125 (253 U/ml). Pathological history of absence crisis in treatment with ethosuximide. Results: A right adnexectomy was performed. Macroscopy showed a large solid tumour with geographic pattern. Histology revealed a spindle cell neoplasm with rounded nuclei, arranged in an anarchic pattern. Alternating hypo- and hypercellular areas, the latter with cells with enlarged nuclei, occasional nucleoli and up to 7 mitoses/HPF. After 2 weeks, due to clinical worsening of the patient, omentectomy and biopsy of the intestinal serosa were performed. Microscopy showed extensives areas of sclerosing fibrosis and fibroblasts with oval isomorphous nuclei without atypia or evident proliferative activity. Immunohistochemical stains were positive for PR, Calretinin, and negative for Desmin, Inhi- bin, CD34, CKAE/AE3, ER, SMA, C-kit in ovarian. Sclerosing perito- nitis was positive for Calretinin and negative for PR, Inhibin. Conclusion: Usually, LTSP presents in the third decade and is bilateral in 84-90% but few cases have been reported between the ages of 12-17 years and one of them with a history of treatment with ethosuximide. The appropriate treatment is unclear but surgery is one of the main therapeutic measures. Our patient received high-dose corticosteroids as first line, then gonapeptyl for 7 months and is currently on mainte- nance tamoxifen without signs of relapsed until the time of this study. E-PS-10-065 The significance of histological and immunohistochemical studies in the diagnosis of chronic endometritis in infertility Z. Zhalimbetova*, B. Ibraimov *Corporative fund University Medical Center, Kazakhstan Background & objectives: To determine the diagnostic significance of endometrial biopsy in establishing the cause of infertility. Methods: 30 women diagnosed with infertility were examined. With the help of endometrial biopsy, histological, immunohistochemical studies of the endometrium were carried out. Results: According to the results of the study, it was found that in 20 women, the expression of ER and PR receptors in the glands corre- sponded to the morphological picture, and in the stromal component, the expression of ER and PR were reduced; 8 patients had severe chronic endometritis, 3 patients had moderate chronic endometritis, 3 patients had mild chronic endometritis, and it was also found that endometrial pathology was noted in 11 patients. So, glandular, glandular-fibrous polyps in 7 women, and glandular endometrial hyperplasia - in 4. Conclusion: The immunohistochemical method of research is highly specific and highly sensitive and allows to reliably identify the types of the inflammatory process, also chronic endometritis is one of the leading causes of infertility, violation of the endometrial receptor appa- ratus, are detected in almost all patients with chronic endometritis. The analysis of the data obtained allows us to conclude that the use of a comprehensive study in women with infertility is a necessary condition at the stage of preparation for IVF. E-PS-10-066 Ganglioglioma arising from ovarian mature cystic teratoma: report of a rare case Z. Zhao*, P.Y. Tang, S.H. Chew *Department of Anatomical Pathology, Singapore General Hospital, Singapore Background & objectives: Somatic neoplasms occasionally arise in ovarian teratomas, however, central nervous system (CNS)-type neu- roepithelial tumours are rare, mostly glial neoplasms and embryonal tumours. Here we present a rare case of ganglioglioma arising from ovarian mature cystic teratoma of a 30-year-old female. Methods: Our patient underwent ovarian cystectomy for an inciden- tally found 6.8 cm dermoid cyst. Microscopically, components from all three germ layers were identified. Focal glioneuronal tissue showed increased glial cellularity with mild cytologic atypia and rare accom- panying perivascular lymphoid aggregates. There were intermixed, dispersed dysmorphic neurons, with cytomegaly, perimembranous aggregation of Nissl substance and occasional binucleation. Hardly any mitoses were seen. Results: In this case, increased cellularity in the glial tissue at low power raised the possibility of a low-grade glial neoplasm, such as astrocytoma, or reactive gliosis. However, dysmorphic neurons identified at higher power suggested a glioneuronal tumour instead. The diagnosis of ganglioglioma