ECP 2023 Abstracts

S267 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 The morphological and immunohistochemical findings were consistent with SMFGT, in association with prior tamoxifen treatment. Conclusion: SMGT is usually located at the vulva, vagina, or cervix. It’s a benign tumour and very rarely recurs after complete surgical excision. SMFGT originates from pluripotent primitive cells but is commonly related with tamoxifen treatment. It should be included in the differential diagnosis of more common mesenchymal cervical tumours. E-PS-10-056 HPV-independent adenocarcinoma of the uterine endocervix of endometrioid type: a case report on a rare entity F. Sousa Vieira*, A.P. Rodrigues, D. Sá, S. Neves, G. Carrola, J.R. Vizcaíno, N.J. Lamas *Centro Hospitalar Universitário de Santo António, Portugal Background & objectives: Endocervical adenocarcinoma is a malig- nant epithelial neoplasm arising in the cervix whose incidence has increased, especially in developed countries, accounting for up to 25% of cervical tumours. Nearly 10-15% of cases are HPV-independent. Methods: Here, we report the case of a 74-year-old woman diagnosed with HSIL in gynaecological screening, who underwent cervical conization, having HSIL-positive surgical margins. For this reason, the patient was subsequently submitted to total hysterectomy with bilateral adnexectomy. Results: No relevant macroscopic findings were found, but the histo- logical analysis revealed an endocervical neoplasm forming tubular glands, in many areas replacing the cells of pre-existing endocervical glands; alternating with areas of confluent growth and with features suggestive of stromal invasion. Neoplastic cells showed high nucleus- to-cytoplasmic ratio, cytological atypia, increased mitotic activity and apoptotic bodies were identified. The neoplastic cells were immunore- active for PAX-8, CK7, ER and PR. p16 showed a “patchy” staining, while p53 had “wild-type” expression and MMR proteins expression was preserved. The proliferative index (%Ki-67) was nearly 30-40%. Adenocarcinoma was not identified in the lower uterine segment, nor in other endometrial areas, which were fully submitted and analysed. Conclusion: A diagnosis of primary endocervical adenocarcinoma, HPV-independent, of endometrioid type, in a background of adenocar- cinoma in situ of endometrioid type was performed. This is an exceed- ingly rare case, which represents less than 1% of primary endocervical adenocarcinomas. This diagnosis can only be established after exclu- sion of endocervical extension of primary endometrial adenocarci- noma, HPV- dependent adenocarcinoma or mesonephric carcinoma. The patient remains well and without evidence of disease recurrence one year after surgery. E-PS-10-057 Perivascular epithelioid cell tumour of broad ligament of uncertain malignant potential - a cases report G. Stanc*, E. Souka, C. Iavazzo, O. Tzaida, C. Valavanis, H. Trihia *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: Perivascular epithelioid cell tumours (PEComas) are mesenchymal neoplasms composed of cells which express both melanocytic and myogenic markers. PEComas of the female genital tract account ≈25% of all PEComas in all body sites. Methods: A 37-year-old female was referred to our hospital with an incidentally found large mass of the left broad ligament. Surgical exci- sion was performed and a circumscribed tumour 5X4X2cm in dimen- sions was sent to the Pathology Department. On gross examination the tumour showed a tan to white cut surface. No areas of necrosis were recognized. Results: The microscopic examination revealed a high cellular epithe- lioid neoplasm, with diffuse and nested pattern. The neoplastic cells showed abundant eosinophilic cytoplasm with mild to moderate nuclear atypia. The mitotic activity was low to absent – up to 2-3 mitoses/ 50HPF, with atypical forms. No necrosis, multinucleated giant cells or vascular invasion were present. Stromal hyalinization was recognized focally. Immunohistochemical examination was positive for Melan A, MITF, Vimentin, ER, HHF-35, SMA and Ki-67 was positive in 5% of tumour cells. Negative immunostaining was observed for CD10, CKAE1/AE3, CK 8/18 and S-100. A final diagnosis of perivascular epithelioid cell tumour of uncertain malignant potential was made. Conclusion: Prognosis is favourable in the majority of PEComas and surgery is considered the first line of therapy. A small percentage of these tumours showed recurrence years after original diagnosis and long-term surveillance is recommended. Chemotherapy and radiation may be administered in patients with met- astatic or recurrent disease. The mTOR inhibitors have shown variable results especially in the neoplasms with TFE3 fusions. E-PS-10-058 Primary vulvar adenocarcinoma of intestinal type: report of two cases showing molecular similarity with colorectal adenocarcinoma S. Stolnicu*, A. Palicelli, T. Maloberti, D. de Biase, A. De Leo, M. Lindh, K. Stenström Bohlin, C. Mateoiu *Department of Pathology, UMFST Gh E Palade of Targu Mures, Romania Background & objectives: Vulvar adenocarcinoma of intestinal type (VAIt) is uncommon. In an attempt to clarify the aetiology, clinico- pathologic spectrum of this neoplasm and to inspire additional research into their biology, two more cases of VAIt are reported, including immunohistochemical and molecular analysis. Methods: Two VAIt cases were identified and stained for immuno- histochemical markers. After DNA extraction using DNA isolation, I kit on a Magnapure LC instrument (Roche Molecular, Mannheim, Germany), amplification was performed in 15 separate real-time Poly- merase chain reactions, one for each of the 14 Human Papillomavirus types and one for beta-globin. Targeted Next-generation DNA sequenc- ing was used to assess somatic mutations. Results: Two patients of 63 years old each presented with an exophytic vulvar mass. At microscopic examination, a primary adenocarcinoma resembling a colorectal cancer, was identified in both cases. The infiltra- tive area displayed a glandular architecture, with glands of variable size and shape, lined by columnar to cuboidal cells with large nuclei and coarse chromatin; goblet cells were present. Based on microscopic and immuno- histochemical analysis both tumours were diagnosed as HPV-independent VAIt FIGO stage 1. Both cases harboured pathogenic somatic mutation of TP53 (Case 1: p.Arg248Gln; Case 2: p.Gly266Glu). In addition, case 1 displayed pathogenic somatic mutation of KRAS (p.Gly12Asp) and case 2 showed DPYD variant (p.Glu412=/HapB3[AP1]). Conclusion: VAIt is a rare HPV-independent tumour harbouring TP53, KRAS and DPYDmutations similar to colorectal adenocarcinomas which might indicate an increased risk for lymph node and distant metastases but also that they might be resistant to chemotherapy and might respond to anti-epidermal growth factor receptor (EGFR) antibody therapy. E-PS-10-059 Ovarian gynandroblastoma of unusually large size in a 44-year-old woman: a case report with immunohistochemical analysis A. Sykaras*, N. Stavrinou, F. Dolkiras, E. Spiteri, C. Magkou *Department of Pathology, Evangelismos General Hospital, Athens, Greece Background & objectives: Ovarian Gynandroblastoma (GAB) is an extremely rare sex cord stromal tumour consisting of both male and female components. The male element is Sertoli/Sertoli-Leydig cell