ECP 2023 Abstracts

S330 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 examination, the foetus presented with diffuse pulmonary lymphangi- omatosis and foci of extramedullary hematopoiesis in the liver. The blad- der muscular wall showed hypertrophy and denuded urothelium. Overall, the autopsy findings confirmed the antenatal diagnosis of DiGeorge syn- drome with tetralogy of Fallot and revealed several other malformations. Conclusion: This case report highlights the challenges in accurately diagnosing and managing complex congenital anomalies such as DiGeorge syndrome and tetralogy of Fallot. Despite antenatal diagno- sis, the patient’s clinical course was complicated by multiple systemic abnormalities, resulting in cardiorespiratory arrest and death. Autopsy findings revealed thymus hypoplasia, not agenesia, and other extensive malformations affecting various organs that were not diagnosed antena- tally. This case emphasizes the importance of early and comprehensive evaluation of foetal anomalies in order to improve patient outcome. E-PS-19-004 An unusual location of a synovialosarcoma in a child, a case report A. Bdioui*, L. Jaidane, S. Mestiri, A. Baccouche, O. Belkacem, S. Hmissa *Sahloul Hôpital of Sousse, Tunisia Background & objectives: Malignant cardiac tumours are rare, espe- cially in a paediatric age. It is dominated by the rhabdomyosarcoma, synovialosarcoma is exceptional. We report a case of a 12-year-old child, for which a cardiac synovialosarcoma was discovered. Methods: We report a case of a 12 year old boy, without significant pathological history, who presents to the emergency room in a state of cardiogenic choc. He was admitted to the intensive care unit. A cardiac echography highlighted an intra cavitary mass. Results: The material brought back was friable yellowish, mimicking a mass of 10 cm. it showed, microscopically, a hypercellular malignant tumoral proliferation infiltrating the ventricular muscle. This prolifera- tion was arranged in storiform pattern composed with monomorphic ovoid cells. The atypia was slight. The figures of mitosis were numer- ous. The stroma, richly vascularized, showed a haemangiopericidal appearance. On immunohistochemistry the tumour cells were positive for TLE and focally for CD99. However, they were negative for EMA, AML, Desmin, CD34, Erg and for Myod1. Conclusion: However, this entity is rare, it is not exceptional. The sites of predilection are the pericardium followed by the left ventricle. Although the recruitment of cardiac surgical specimens is frequent in our department, only one case of ventricular synovialosarcoma has been identified in recent years. E-PS-19-005 Misleading presentation of an inflammatory myofibroblastic tumour of maxillary sinus, a report of a paediatric case A. Bdioui*, K. Bilazreg, A. Baccouche, O. Belkacem, S. Mestiri, S. Hmissa *Sahloul Hôpital of Sousse, Tunisia Background & objectives: Inflammatory myofibroblastic tumour (IMT) is a rare neoplasia, occurring primarily in the viscera of children and young adults. The head and neck region is relatively less commonly involved. Herein we report another rare case of maxillary sinus’ IMT. Methods: A 13-year-old patient with recurrent nasal inflammatory pseudoplyposis, presented in the department of maxillo facial surgery for tumour of right maxillary sinus with epistaxis. He underwent a surgical biopsy. We received whitish and haemorrhagic small specimen, whose size varies between 0.4 and 3 cm. Results: Histologically, the specimen was boarded by respiratory epithelium, lining a lamina propria with abundant lymphocytic and plasmacytic infiltrate. Within this infiltrate, we found scattered cells with abundant amphophilic cytoplasm containing an enlarged nuclei and a distinct nucleoli. There were no necrosis and no mitotic activity. The first suspected diagnosis was Hodgkin lymphoma and rhabdo- myosarcoma, considering the age of the patient and the location of the tumour, therefore, the tumours cells were negatives for CD15,CD30, Myogenin and MyoD1. The case was then presented to a paediatric pathology expert, IMT was evocated, the expression of ALK1 and the morphological features were in line with this diagnosis. Conclusion: IMTs affecting the nasal cavity and paranasal sinuses are rarely described in the english literature. Unlike our case, the cases of IMT in nasal cavity and paranasal sinuses described in the literature can arise in patients of all ages more commonly in adults. The most frequently affected site is the maxillary sinus. Some IMT have large histiocytoid cells resembling ganglion cells or Reed-Sternberg cells of Hodgkin lymphoma. The presence of these cells is related to poorer clinical outcomes. E-PS-19-006 Rare simultaneous appearance of maternal neuroendocrine carcinoma and giant placental chorangioma in a preterm male pregnancy D.P. Burlacu*, A. Burlacu, B. Szabo, T. Mezei *Department of Pathology of Emergency Clinical Hospital of Targu- Mures, Romania Background & objectives: Giant placental chorangioma (GPC) is a rare indolent vascular tumour greater than 5 cm, affecting 1 in 10.000 female pregnancies. We report the case of a GPC occurring in a pre- term male pregnancy complicated with congestive heart failure. Methods: A normotensive, nondiabetic 30-week primigravida was admitted to our hospital complaining of severe abdominal pain. Medi- cal history revealed an advanced-stage rectal neuroendocrine carcinoma. Ultrasonography showed a morphologically normal foetus, except for cardiomegaly. A well-vascularized placental tumour with arterio-venous shunts was also discovered. A C-section was performed, and a 1500 g premature male foetus with congestive heart failure was delivered. Results: A 16x14x2.5 cm placenta weighing 577 g with a tan, fleshy tumour near the umbilical cord measuring 13.5x11.5 x 6.5 cm, weigh- ing 412 g, was submitted to our Pathology Department. Microscopi- cally, the tumour was unencapsulated but well-circumscribed, with a lobular architecture mainly composed of congested vascular capillaries and thin-walled vessels. Immunohistochemistry revealed CD31-posi- tive endothelial cells lining the vessels. Cytokeratin 18 focal positivity suggested a chorionic plate and anchoring villi origin of the vessels. No mitotic figures nor significant cytological atypia were encountered. Given the dimensions and weight of the tumour, a diagnosis of giant placental chorangioma (GPC) was rendered. Conclusion: GPC is a rare and challenging condition. Typically, it occurs in hypertensive or diabetic primigravidas with female foetuses. GPC in a preterm male pregnancy complicated with foetal congestive heart failure highlights the importance of timely antenatal diagnosis and appropriate management to prevent possible complications in order to provide a favourable perinatal outcome. To our best knowledge, this is the first case reporting the existence of a maternal neuroendocrine carcinoma associated with a benign placental tumour. E-PS-19-007 Human herpesvirus 6 associated encephalitis with fulminant brain oedema in a 5-month-old child: a case report J. Carneiro Melo*, Á. Macêdo Freire, G. Carvalho de Freitas Soares, B.R. Novais Lima, S. Samuel Feitosa Machado, R. Beserra Landim, C. Gleidiston Lima da Silva *Univesity of Fortaleza, Brazil Background & objectives: Human Herpes Virus 6 (HHV-6)’s infec- tions occur mainly during childhood, causing a variety of clinical