ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Microscopically, the lesion was morphologically heterogeneous, consisting of a poorly differentiated transitional component (IHC: GATA3+, p63+) interspersed with areas of mucinous carcinoma of intestinal type (IHC: CK7-, CK20+/-, CDX2+, SATB2-, GATA3-). In addition, areas of borderline and benign Brenner tumour were present. The neoplasm was confined to the ovary. Molecular analy- sis by NGS panel identified PIK3CA and TP53 mutations in both components. Patient is disease-free at 24 months after diagnosis and adjuvant chemotherapy. Conclusion: Although benign Brenner tumours with a mucinous component are relatively common, the combination of a primary ovarian mucinous carcinoma with a malignant Brenner tumour is unique and has been exceptionally reported in literature. Integra- tion of an adequate immunohistochemical profile and molecular analysis is crucial for a correct diagnosis. E-PS-09-042 An exceptional case of primary ovarian angiosarcoma L. Di Sciascio*, A. Orsatti, D. de Biase, T. Maloberti, A.G. Cor- radini, F. Rosini, D. Santini, A. De Leo *Pathology Unit, University of Bologna Medical Center, Italy Background & objectives: Primary angiosarcomas of the ovary are exceptionally reported neoplasms, some of which associated with mature teratomas. The aim of the study is to present the clinico- pathological and immunohistochemical features of a case of ovarian angiosarcoma. Methods: Clinical data and history were extracted from the patient’s medical records. An extensive immunohistochemical profile was performed together with molecular analysis by Next- Generation sequencing panels and in situ hybridization. Results: A 40-year-old patient, with a previous resection of ovar- ian mature teratoma, underwent bilateral hystero-annessiectomy, omentenctomy, and peritoneal biopsy for a right ovarian mass suggestive for malignancy. Microscopic examination showed a high-grade neoplasm of predominantly undifferentiated appear- ance with extensive areas of haemorrhage and necrosis. Tumour cells were epithelioid and spindle with marked pleomorphism and prominent nucleoli. Mitotic rate was of 3 mitoses/HPF. Peripher- ally, the lesion showed abnormal vascular-forming endothelial cells associated with papillary-like projections. The immunohistochemi- cal profile showed negativity for epithelial, melanocytic, sex-cord and muscular markers. Diffuse and strong expression of CD31, ERG and partial expression of CD34 and CD117 were present. No significant genetic and molecular alterations were observed. Conclusion: Ovarian angiosarcoma is a challenging diagnosis that requires an accurate microscopic evaluation. Only few cases have been reported in literature. Histological features include the presence of undifferentiated and proliferating tumour cells with epithelioid and spindle appearance, associated with aberrant vessels and a marked CD31 positivity. It is also crucial to rule out all the other histotypes characterized by morphological overlapping (i.e. melanomas, carcinomas, sex-cord tumours and sarcomas). E-PS-09-043 Clinicopathological features of two ultra-rare cases of malig- nant Perivascular Epithelioid Cell Tumours (PEComas) involv- ing uterus B. Rekhi*, S. Menon *Department of Surgical Pathology/Tata Memorial Hospital, Parel, Mumbai, India Background & objectives: Malignant perivascular epithelioid tumours (PEComa) involving the uterine corpus are extremely uncommon tumours. Herein, we present clinicopathological features of two such rare cases. Methods: Case1 A 62-year-old-lady presented with vaginal bleed- ing. Ultrasonogram revealed a heterogeneous uterine mass. She underwent endometrial biopsy and total abdominal hysterectomy with bilateral salpingo-oophorectomy(TAH-BSO), which revealed 3.2 cm-sized proliferative tumour in the fundus. Cae2 A 45-year-old-lady presented with recurrent abdominal pain. She underwent cytoreductive surgery twice with adjuvant chemo- therapy for multiple tumours and TAH-BSO for uterine tumour, 2 years back. Results: Microscopic examination in both cases revealed hypercel- lular tumours composed of markedly atypical, polygonal-shaped/ epithelioid cells arranged in nesting pattern with intervening blood vessels, containing eosinophilic cytoplasm, mitotic figures (≥6/10 hpf) and tumour necrosis. Tumour infiltration was more than half the myometrial thickness in the first case with pelvic nodal metas- tasis. The second tumour revealed rhabdoid-like and vacuolated cells along with scattered osteoclastic giant cells. Immunohisto- chemically, both tumours were positive for HMB45 and desmin while negative for S100P and epithelial markers. The second tumour was also positive for SMA and TFE3. Both patients devel- oped tumour recurrences. In view of multiple tumour deposits, the second patient was induced on m-TOR inhibitor everolimus. Conclusion: Malignant PEComas involving the uterus are extremely rare tumours. An index of suspicion, based on certain histomorphological features, supported by immunohistochemical expression of myomelanocytic markers is necessary for a correct diagnosis. Certain PEComas display TFE3 positivity. A correct diagnosis has significant implications, including an aggressive clinical course and the possibility of targeted therapy, especially in recurrent or metastatic tumour settings, as observed in our sec- ond case. E-PS-09-044 Hydatiform mole: clinico-pathological characteristics in the central Tunisian region Z. Nfikha, N. Abdessayed*, S. Mabrouk, A. Bchir, Y. Fejji, M. Mokni *Department of pathology, Farhat Hached University Hospital, Sousse, Tunisia Background & objectives: Hydatidiform mole is defined as a partial or complete hydropic degeneration of the chorionic villi with vari- able degree of trophoblastic cells proloferation. It is a heterogeneous group of rare and aggressive disease which evolution may be marked by malignant transformation. Methods: we aim to investigate the clinical and pathological char- acteristics of hydatidiform mole. This is a retrospective study of 59 cases of hydatidiform mole. The cases were collected in the department of pathology of the Farhat Hached Hospital, Sousse, Tunisia over a period of 5 years [2016-2020]. Results: The mean age of our patients was 35 years. Metrorrha- gia in a context of amenorrhoea was the most frequent revealing symptom (80%). BHCG levels were high in 100% of cases. Ultra- sound examination was suggestive of molar pregnancy in 71% of cases. Endouterine aspiration was performed in 96% of the patients. Urgent hysterectomy was performed in two cases due to the abun- dance of metrorrhagia. Histological examination found complete mole in 36 cases (61%) and partial mole in 23 cases (39%). The evolution was marked by transformation into invasive mole in 3 cases (4%), confirmed on postoperative hysterectomy specimen. S267