ECP 2023 Abstracts

S266 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 relapses. We search for genomic differences between relapsing and non-relapsing carcinomas using whole exome sequencing (WES). Methods: Twelve carcinomas were analysed by WES, half from patients with relapse. DNA was extracted from formalin-fixed paraf- fin-embedded blocks. Capture was done using xGen Exome Research Panel. After alignment, variant calling and filtering was performed using VarSome Clinical v10.2. Tumour mutational burden (TMB) was calculated and KEGG cancer pathways were screened to perform an overrepresentation analysis (ORA). Results: TMB was increased in patients with mismatch repair defi- ciency. One tumour had nearly double the TMB of the second highest and was found to have a pathogenic POLE mutation. Most recurrent mutated genes were PTEN (9 mutations in six patients) and ARID1A (5 mutations in four patients). ORA showed that PI3K-Akt signalling pathway accumulated the highest number of pathogenic mutations, followed by FoxO signalling, which was the most frequently mutated pathway among non-relapsing patients. Members from the Ras sig- nalling pathway were the most recurrently mutated among relapsing patients. It was also the most differentially mutated pathway between relapsing and non-relapsing patients, followed by Wnt signalling and Hippo signalling pathway. Conclusion: PTEN is a tumour suppressor gene that is frequently mutated in low grade, early-stage endometrial carcinomas. In these subgroups, Ras signalling pathway and CTNNB1 mutations are poten- tial markers for identifying patients at higher risk of relapse. Funding: This research was funded by the Instituto de Salud Carlos III (ISCIII) (PI17/01723 and PI21/00920), cofinanced by the European Development Regional Fund ‘A way to achieve Europe’ (FEDER). E-PS-10-053 Confocal microscopy in the evaluation of uterine transplantation biopsies A. Saco*, N. Rakislova, L. Marimón, N. Carreras, E. Barnadas, L. Sisuashvili, M. Rius, B. Diaz-Feijoo, F. Carmona, J. Ordi *Hospital Clínic, Barcelona, Spain Background & objectives: Control of rejection after uterine transplan- tation includes protocolized biopsies, which require urgent evaluation. Confocal microscopy (CM) allows providing histological diagnoses a few minutes after sampling. We aimed at assessing the accuracy of CM in the interpretation of transplantation biopsies. Methods: Seventeen cervical biopsies from two uterine transplantation recipients were evaluated using CM (VivaScope 2500-G4) immediately after sampling. Following routine histological processing all biopsies underwent a second evaluation by an independent pathologist (final diagnosis, FD). The Brännström criteria were used in both evaluations. Discordances were classified as “major” or “minor” depending on the impact on management. The interobserver agreement was evaluated. Results: The FD were: 11 no rejection, two borderline changes, one grade 1 rejection, three insufficient. Additionally, five biopsies showed a low grade squamous intraepithelial lesion (LSIL). The inter-observer agreement was complete in 82% of the biopsies (13 samples). Three of the discordances were classified as major discrepancies (two cases diagnosed as rejection, one borderline and one grade1 by CM, that were negative in the FD; one negative biopsy with CM diagnosed as border- line rejection in the FD) and one showed a minor discrepancy. LSIL was successfully diagnosed in all cases. Three out of the four (75%) dis- crepancies were detected in the first weeks after CM implementation. Conclusion: Confocal microscopy has a good concordance with the conventional microscopy evaluation and can be successfully used in the assessment of control cervical biopsies from uterine transplantation recipients. The technique allows providing a diagnosis a few minutes after sampling and is an adequate option for biopsies requiring urgent evaluation, such as uterine transplantation biopsies. Nevertheless, an adaptation and learning process is recommended before relying on confocal microscopy results to avoid under or overtreatment of rejection. E-PS-10-054 About a rare case of cervical localisation of uterine tumour resem- bling an ovarian sex cord tumour G. Sahraoui*, F. Sassi, F. Ltaief, R. Doghri, A. Amara, L. Charfi, K. Mrad *Salah Azaiez Institute, Tunisia Background & objectives: Uterine tumour resembling an ovarian sex cord tumour (UTROSCT) is a rare histological type of endometrial stromal and related tumours according to the latest WHO classification of female genital tumours. Here, we report the third case of a cervical UTROSCT. Methods: A 19-year-old woman presented with a history of lower abdominal pain and irregular menstrual cycles. Gynaecological exami- nation revealed a firm mass in the cervical region. The vulva, urethra and vagina were normal. Computed tomography was performed show- ing a 30 mm mass arising from the cervix. A cervical lumpectomy was performed. Results: Microscopically, the tumour exhibited nested and trabecular patterns. Tumour cells ahd abundant cytoplasm, ovoid and spindle- shaped nuclei with fine chromatin. Mitoses were <1/10 HPF. A delicate vascular network of small capillaries was observed. Immunohistochem- ically, the tumour cells were positive for Calretinin, AE1/AE3, Desmin, progesterone receptors, SMA and h-caldesmon, while being negative for CD10, WT1, Myo D1, HMB45, ALK, EMA, and Inhibine. Based on these observations, the diagnosis of cervical UTROSCT was made. No metastasis was detected in the omentum or lymph nodes, and the tumour was classified as stage IB according to the International Federa- tion of Gynaecology and Obstetrics tumour staging system. The patient had an uneventful recovery after surgery. Conclusion: This case highlights the clinical presentation, diagnos- tic evaluation, and management of a cervical UTROSCT in a young patient, providing significant insights into this rare condition. Early recognition and prompt surgical intervention are essential to achieve favourable outcomes. E-PS-10-055 A rare case of superficial myofibroblastoma of the lower genital tract E. Souka*, G. Stanc, G. Galanopoulos, C. Iavazzo, H. Trihia *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: Superficial myofibroblastoma of the lower female genital tract (SMFGT) is a benign mesenchymal neo- plasm increasingly recognized in the vagina and less often the cervix or vulva. We present a rare case of cervical SMFGT and short review of the literature. Methods: A 51-year-old female with a past medical history of breast cancer and tamoxifen therapy, presented with metrorrhagia. On gynaecologic examination there was a well-circumscribed submu- cosal mass of the cervix, clinically consistent with a cervical fibroid. The patient underwent excisional biopsy of the mass. On gross examination the mass was submucosal, circumscribed, solid, white-tan, 3.4 cm in greatest diameter. Results: Microscopic examination revealed a well-circumscribed, non-encapsulated hypocellular tumour. The neoplasm was composed of bland spindle cells with vaguely fascicular growth and inter- spersed thick collagen bundles or lacelike pattern, in a loose oedema- tous stroma. There was minimal mitotic activity or necrosis. Immu- nohistochemical examination revealed a Desmin(+), Calponin(+), SMA(-), CD34(+), BCL-2(+), CD99(+), ER(+), phenotype.