ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 woman. The tumour was a primary carcinoid tumour arising from the endometrium which showed as a polipoid mass, with the typi- cal organoid patterns with a positive reaction for neuroendocrine markers. No evidence for the carcinoid syndrome was noted. She remains free of disease. Conclusion: Scant reports in the literature prohibit any reliable prediction of uterine carcinoid prognosis. Thus, prompt identifica- tion of the disease and subsequent therapeutic intervention could alter the final outcome. E-PS-09-037 HER2 expression and mismatch repair status in endometrial clear cell carcinoma S. Yilmaz Erozbek*, Z. Bayramoglu, I.A. Ozdemir, V. Ulker, B. Muezzinoglu *Istanbul Medipol University, Pathology Department, Turkey Background & objectives: High-grade endometrial carcinomas (HGEC) are difficult to classify. With the current use of HER2-based therapy in serous carcinoma, a diagnosis of CCC has the potential to exclude patients from receiving therapy. Therefore, we examined HER2 expression in our CCC patients. Methods: Immunohistochemically, HER2, ER, PR, HNF1β, Napsin A, MLH1, MSH2, MSH6 and PMS2 were applied to 8 endometrial CCC cases diagnosed between 2016-2022. HER2 staining pattern, ASCO/CAP protocol used for breast was used. Results: HER2 was positive in 3 of our 8 CCC patients (37.5%). While all of our HER2+ cases were Napsin A and HNF1β posi- tive, MMR proteins were intact and ER and PR were negative. Two patients had wild type p53 and 1 patient had aberrant p53 staining. Conclusion: The fact that 37.5% of our CCC cases were HER2+ is a finding with strong implications for the therapeutic approach. As a result of our study, in patients with CCC, if MMR is intact and ER-PR is negative, regardless of the p53 staining pattern, HER2 testing may be an objective screening method for patients who are likely to benefit from HER-targeted therapy. Consequently, patients with a diagnosis of CCC can be candidates for future clinical trials of HER2-targeted therapy. E-PS-09-039 Evaluation of PD-L1 expression in vulvar cancer G. Sahraoui*, M. Manai, N. Kouki, H. Douik, L. Charfi, M. Bou- hani, R. Mchiri, N. ben hamida, K. Mrad, R. Doghri *Pathology Department, Salah Azaiez Institute; Research Labora- tory LR21SP01, Tunis, Tunisia Background & objectives: The PD-L1 pathway role is still debated in gynaecological malignincies. We analysed PD-L1 expression in vulvar cancer by immunohistochemistry and its correlation with histoprog- nostic factors. Methods: A retrospective study was conducted in the Pathology Department of Saleh Azaiez Institute, involving 55 patients fol- lowed for vulvar cancer over a period of 13 years, from January 2008 to December 2021. Clinicopathologic data were collected from medical records and pathology reports. Immunohistochemical analysis was performed using an automaton (LeicaBiosystems™). Results: PD-L1 expression in vulvar squamous cell carcinoma was observed in 44% of cases. This expression was noted in 11% of cases at the level of lymphocytes. Lymph node dissection was negative among all these cases with a maximum tumour size of 40 mm. PD-L1 was expressed in tumour cells in 33% of cases. Among them, positive inguinal dissection was observed in 22% of cases, with a maximum tumour size of 90 mm. Conclusion: PD-L1 expression was detectable in a subset of vulvar squamous cell carcinoma. Cases with PD-L1 expression on tumour cells showed less favourable histoprognostic factors, which sug- gests its implication in tumour progression. The PD-1/PD-L1 path- way represents a promising prognostic factor and therapeutic target that may optimize the therapeutic management of vulvar cancer. E-PS-09-040 Vulvar fibroadenoma: a case report J. Carneiro Melo*, G. Oliveira Muniz, Y. Portela Velez, G. Torres Alves de Carvalho, D. Nunes Oliveira, G. Ferreira Morgantetti, G. Alencar Medeiros, G. Azevedo Silveira, G. Barbosa Torres Bitu *University of Fortaleza, Brazil Background & objectives: The vulvar fibroadenoma is a rare oli- gosymptomatic benign nodular tumour. The most accepted theory about its origin is the failure of milk line regression in embryonic development. Methods: This is a case report of a vulvar fibroadenoma in a 40-year-old female patient with a vulvar ulcerated lesion that has not healed for 6 months. Results: The patient reported a left vulvar lesion that had not healed for 6 months. Biopsy was performed, obtaining a fragment of skin at subcutaneous level. Macroscopy revealed a single hypochromic, elevated, asymmetric lesion with a regular border, with dimensions 0.7 x 0.7 cm in area and 0.5 cm thick. Microscopy showed glands in a lobular pattern similar to mammary tissue, with cystic changes and apocrine metaplasia. Compressed ducts were seen in the dense fibrotic stroma, similar to breast fibroadenoma. Without evidence of mitosis figures and other signs of malignancy. Conclusion: The occur rence of vulvar fibroadenoma is extremely rare in the literature, there are about 60 cases described in the world. With this, there is a need to disseminate information about this pathology so that cases like this can be clarified. The case reported has aspects in agreement with those reported in the world literature, such as the patient’s age group and the characteristic of the lesion, which is elevated and has irregular edges. E-PS-09-041 Ovarian mixed malignant Brenner-mucinous tumour: report of a unique case A. Orsatti*, L. Di Sciascio, D. de Biase, T. Maloberti, G. Tallini, A.G. Corradini, F. Rosini, D. Santini, A. De Leo *Pathology Unit, University of Bologna Medical Center, Italy Background & objectives: Malignant Brenner tumour is a rare ovar- ian carcinoma. The presence of an associated malignant mucinous component is exceptionally reported. This study aims to describe the pathological and immunohistochemical features of a unique case of ovarian mixed malignant Brenner-mucinous tumour. Methods: Clinical data and history were extracted from the patient medical records. Immunohistochemical (IHC) analysis and molecular characterization by Next-Generation sequencing were performed. Results: A 65-year-old woman underwent surgery for a 5 cm left ovarian lesion. Gross examination revealed a partly cystic, multi- loculated mass filled with abundant gelatinous mucinous substance. S266