ECP 2023 Abstracts

S88 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 PS-10-013 A clinicopathologic analysis of somatically derived germ cell tumours of the female genital tract M. Fukunaga* *Shin-yurigaoka General Hospital, Japan Background & objectives: Female genital tract malignant epithelial neo- plasms with germ cell tumours (GCTs) are very rare and pose diagnostic and therapeutic challenges. This type of neoplasm usually arises in post- menopausal females. The objective is to clarify the clinicopathologic fea- tures and its histogenesis. Methods: A total 18 cases of these neoplasms with GCTs in patients aged 40 years or over, except one of 31 years, were clinicopathologically and immunohistochemically studied. Results: The age of the patients ranged from 31 to 79 years. Eight tumours were in the endometrium, 6 in the ovary, 2 in the tube, one each in the cervix or peritoneum. Five each had choriocarcinoma, hepatoid carcinoma, or yolk sac tumours (YSTs), two had immature teratomas and one had YST and hepatoid carcinoma. There were malignant epithelial tumours comprising high-grade serous carcinoma (n=7), endometrioid carcinoma (n=3), large cell neuroendocrine carcinoma (n=3), clear cell carcinoma (n=3), and gas- tric type mucinous carcinoma (n=2). There was some immunophenotypic overlap with carcinomas and YSTs. Follow-up data were available in 11 cases. Six died of the disease within 12 months (mean: 8.5) after surgery. Conclusion: The findings suggest the association between GCT and epi- thelial malignant neoplasm, with the former probably arising from the latter through a process of neometaplasia or retrodifferentiation in the female genital track. Somatic epithelial neoplasm can be of various histologic types. This type of tumour can occur in young patients. Its recognition is necessary in view of its unusually aggressive behaviour and associated poor prognosis. Adjuvant chemotherapy regimens should include platinum-based chemotherapy, aiming at treatment for both carcinoma and GCT. PS-10-014 Histologic findings in hysterectomy and oophorectomy specimens in individuals undergoing gender-affirming surgery J. Gama*, F. Ramalhosa, J. Madeira, V. Almeida, C. Courelas, J.L. Amaral, B. Sepodes, A. Alves, J. Pimentel, M.A. Cipriano *Centro Hospitalar e Universitário, Portugal Background & objectives: Gender-affirming surgery is increasingly common and it is part of the process of gender transitioning. Histologi- cal changes that may happen under hormonal treatment are important to recognize and are not yet fully described. Methods: A retrospective study (2016-21) was carried out. Clinical and pathological data were retrieved from the hospital database. Histo- logical evaluation of the surgical specimens was performed, all surgical gynaecologic pathology and cytology slides were reviewed. Results: A total of 28 patients were included, which represented 28 hysterectomy and bilateral salpingo-oophorectomy specimens, 2 vaginectomy specimens and 5 cervical cytologies. The median age at surgery was 29 years and all patients were under treatment with testosterone. Twenty-one patients (75%) exhibited transitional cell metaplasia of the cervix and 2 of the vagina (100%). Prostatic-type glands were identi- fied in two patients (7.1%). Inactive endometrium was present in 17 (60.7%) patients, active in 10 (35.7%), disordered proliferative in 1 case (3.5%). In two patients (7.1%) adenomyosis was found. The ovaries were mostly multifollicular (27 patients, 96,4%). Of note, one of the patients had a serous borderline tumour of the ovary. Conclusion: Histological changes after hormonal treatment are mostly related to transitional metaplasia of the cervix and vagina. The awareness of these changes, in this population, is important in order to avoid a potential misdiagnosis. The presence, although rare, of pre-neoplastic and neoplastic lesions prompts a careful study of these specimens. PS-10-015 NK cell-mediated antitumour immunity in endometrial carcinoma P. Janega*, M. Kuhnel, A. Janegova *Institute of Pathological Anatomy, Comenius University in Bratislava, Medirex Group Academy, n.p.o., Nitra, Slovakia Background & objectives: Natural killer cells are lymphocytes with cyto- toxic and immunomodulatory activity. In endometrium, they are involved in angiogenesis, nidation of the embryo and its tolerance by the maternal immune system. Their role in tumour transformation in endometrium is not entirely clear. Methods: The pilot study included patients with endometroid carcinoma who met specific criteria (MSS, pT1a). Tumour tissue was assessed for the presence of natural killer cells using immunohistochemistry. CD56+ and CD57+ lymphocytes were quantified in 5 random fields in neoplastic tissue and in surrounding endometrial tissue. Results were compared and correlated with hormone receptor positivity, tumour grade, and patient age. Results: Results of our study showed no significant difference in the pres- ence of CD56+ NK cells between tumour and surrounding non-tumour tissue. However, there was a significant correlation between the number of CD56+NK cells in both areas. CD56+NK cell presence was not correlated with tumour grading or hormone receptor positivity but was negatively correlated with patient age. In contrast, CD57+NK cells were significantly increased in the tumour bed compared to surrounding non-tumour tissue. CD57+ NK cell presence was not related to tumour grading, hormone receptor positivity, nor patient age. Conclusion: The study’s findings indicate that NK cells are involved in endometrial tumour transformation. CD56+ NK cells appear to reflect general immune activation, as their upregulation is seen in both tumour and surrounding tissue. Notably, this activation significantly decreases with patient age. In contrast, CD57+ NK cells are more associated with local immune system activation, suggesting more targeted immune response. Funding: BIOMEDIRES II. phase, 313011W428 PS-10-016 Somatic neoplasms arising from teratomas - a quaternary care centre experience A. Lakshmanan*, N. Mulchandani, S. Naresh Shah, M. Menon, A. Subramanyam *Apollo Hospitals, India Background& objectives: Somatic-type neoplasms (SN) arising from any of the germ-cell elements of teratomas can either be benign or malignant. SNs are mostly associated with mature teratoma (MT) and less commonly with immature teratomas (IT) and mixed germ cell tumours (MGCT). Methods: Over an 8-year-period (January 2014 to December 2022), 1198 reported cases of teratomas, arising at gonadal and extra-gonadal locations were retrieved from the database. We studied 80 cases of SN arising in teratomas to evaluate their morphology and immunohisto- chemistry (IHC) features. The SNs were further categorized as benign, borderline, and malignant. Results: The age range was 10 months - 79 years with a M:F ratio of 1:8. Teratomas were seen most commonly in the ovaries (87.5%), followed by testis (5.8%), mediastinum (2.5%) and the rest in other sites. Pure MT was the commonest diagnosis (90.4%), followed by MGCT (6.3%) and IT (3.3%). The SNs were categorized as benign (n=51; 63.8%), borderline (n=5; 6.2%), and malignant (n=22; 27.5%). Remaining 2 cases (2.5%) showed immature glial proliferation. Mucinous cystadenoma was the commonest benign SN and atypical proliferative serous tumour was the commonest borderline neoplasm.