ECP 2023 Abstracts

S268 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 tumour (SCT-SLCT) whereas the female component consists of either juvenile or adult granulosa cell tumour (JCCT-AGCT). Methods: A 44-year-old woman visited our hospital’s emergency room due to acute abdominal pain. The patient had a well-known history of menstrual disturbances. Abdominal-pelvic Computerized Tomography scan revealed a large solid and partly cystic mass in the pelvic cavity. Due to its size and the possibility of malignancy, the patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Results: The left ovary was replaced by a 38x29x15 cm partly cystic tumour. Microscopically, the tumour consisted of AGCT and SCT areas. The AGCT component was manifesting solid, alveolar, pseudopapillary and nodular growth patterns, within rich fibrous stroma, as well as Call- Exner bodies. On the other hand, the SCT component was well-differ- entiated consisting of tubules of clear cells with basally located nuclei. Immunohistochemically, the tumour cells of both components were posi- tive for inhibin, calretinin, and CD56. CK8/18 was also expressed by both components, although in a dot-like manner in AGCT cells. EMA and CK7 were negative. Based on morphological and immunohisto- chemical features the diagnosis of a gynandroblastoma was established. Conclusion: The present case of GAB has some atypical features. The patient is older than the average GAB patient, the neoplasm is extremely large and its histologic profile represents a relatively uncom- mon combination of well-differentiated SCT with AGCT. Pathologists should be aware of the atypical presentations of GAB and rely on mor- phological criteria. Immunohistochemical analysis can be used to con- firm the sex cord stromal nature of the tumour to establish a confident diagnosis. E-PS-10-060 Unlocking the key to surviving endometrioid carcinoma: a single- centre retrospective analysis A.E. Teles*, F.M. Soares Nogueira, A.S. Carralas Antunes, P. Sequeira, D. Gomes Pinto *Hospital Garcia de Orta, EPE, Portugal Background & objectives: This study aims to assess the impact of histological parameters on patient outcomes in cases of endometrioid or mixed carcinoma with intraoperative consultation (IOC) in a single- centre setting, focusing on endometrial invasion. Methods: We included all patients who underwent IOC for endome- trial lesions at Hospital Garcia de Orta, Portugal between 2015 and 2022. Data were obtained from pathology reports and clinical files. We assessed the impact of histological criteria, including endometrial inva- sion, lymphadenectomy status, number of positive lymph nodes, stag- ing, and grade, on overall survival (OS), using Kaplan-Meier curves and Mantel-Cox tests. Results: Of the initial 85 patients, 70 remained after excluding those without endometrioid or mixed carcinoma diagnoses. The mean age was 68 years. In total, 5 patients died and 5 had recurrence or metas- tasis. There was a significant association (p < 0.0001) between locally advanced tumours (pT2 and pT3) and those with higher histological grades (G2 and G3) with reduced survival rates. Invasion ≥50% of the myometrium was associated with a higher rate of local metastases (p= 0,0026). None of the patients who died had positive lymph nodes. There was no relation between endometrial invasion and lymphadenec- tomy with overall survival. Lymphadenectomy status was not associ- ated with surgical complications in our series. Conclusion: Our analysis found that high pathological staging and histological grade are significantly associated with reduced OS in these patients. IOC enabled lymphadenectomy in patients with a higher local stage, sparing those with early malignancies. It is interesting that we did not find a correlation between lymph node metastases and OS, although that may be attributable to the small size of the series. Our findings highlight the importance of IOC, accurate staging and grading in determining both patients’ prognosis and management. E-PS-10-061 A rare encounter: anastomosing haemangioma and the ovary – case report A.E. Teles*, F.M. Soares Nogueira, C. Dahlstedt Ferreira, P. Seque- ira, D. Gomes Pinto *Hospital Garcia de Orta, EPE, Portugal Background & objectives: Anastomosing haemangioma of the ovary (AHO) is a rare vascular tumour that can be challenging to diagnose and can mimic other ovarian neoplasms. The purpose of this case report is to describe the histopathological features of this benign tumour. Methods: We present a case report of a 69 years-old woman, asympto- matic, who had a history of breast cancer and had been taking tamox- ifen for three months. During a pelvic ultrasound, a cystic mass was detected in her right ovary, later confirmed by MRI. As a result, she underwent a total hysterectomy with bilateral adnexectomy with sub- sequent pathological analysis. Results: On gross dissection, the right ovary weighted 70g and meas- ured 6,3x5,0x3,0cm. In section, the lesion presented a predominant cyst measuring 6,0cm, with a smooth internal wall and haemorrhagic content. The wall showed a whitish nodular area with 1,1cm which was histologically characterized by a complex network of anastomosing thin-walled vessels, layered by endothelial cells with no atypia, that form irregular channels and clefts within a fibrous stroma, without necrosis. Immunohistochemical staining for CD31 and CD34 was posi- tive. Around this vascular lesion, there were hypertrophied stromal cell strongly immunoreactive for inhibin and calretinin. The final diagnosis was AHO associated with hyperthecosis. The remaining ovary showed a seromucinous cystadenoma with ovarian endometriosis. Conclusion: AHO can be present without any specific symptoms or imag- ing features, which requires an accurate histopathologic diagnosis and must include immunohistochemical staining for vascular markers. Surgical resection is the treatment of choice, with excellent long-term prognosis. Our case report highlights the importance of considering AHO as a dif- ferential diagnosis for ovarian tumours (such as angiosarcoma or epithelial ovarian tumours with vascular differentiation), especially in older women, and emphasizes the need for close follow-up in asymptomatic patients. E-PS-10-062 Recurrent extra-gastrointestinal stromal tumours (EGISTs) of the posterior vagina wall with liver metastasis - a cases report C. Valavanis*, E. Souka, E. Kontis, G. Stanc *Molecular Pathology Unit Metaxa Cancer Hospital, Greece Background & objectives: Extra-gastrointestinal stromal tumours (EGISTs) are rare GISTs occurred outside the GI tract. Vaginal tumours account ≈1% of all gynaecological cases and are especially leiomyo- mas. Vaginal GISTs are extremely rare and are considered tumours originated from rectovaginal septum. Methods: A 54-year-old female presented for vaginal bleeding. CT imaging revealed a vaginal mass and a tumour in the liver. Fragments from the vaginal tumour 4X3,5X1,2cm in dimensions were sent for examination along with a liver tumour 5,3X4,5X4,3cm in dimensions after left hepatectomy. Diagnosis of low-grade GIST from posterior vagina wall has been made 5 months ago with no treatment. Results: Microscopic examination of both tumours (vaginal and hepatic) revealed a high-grade gastro-intestinal stromal tumour, with spindle and epithelioid cells morphology and moderate nuclear atypia. Both tumours have high mitotic activity – 15-20 mitoses / 5mm2, no necrosis and immunohistochemically displayed DOG-1 (+), C-KIT (+), CD34 (+) and Ki-67 positivity in 30-40% of the neoplastic cells. Based on the clinical information recurrent high-grade EGIST of the vagina with metastasis in the liver was made. Genetic analysis showed c-kit mutations. Postoperative adjuvant therapy was followed.