ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 *Department of pathology, Farhat Hached University Hospital, Sousse, Tunisia Background & objectives: Paediatric soft tissue tumours are rare heterogeneous group. Although most tumours are benign, developing an appropriate diagnosis requires knowledge of clinical and radiologic characteristics. The objective of our study is highlight the clinico-pathologic characteristic of paediatric soft tissue malignant tumours. Methods: A total of 25 cases of soft tissue malignant tumours diag- nosed in children under 16 years at the Department of Pathology of Farhat Hached University Hospital in Sousse, over a period of 16 years (from 2005 to 2020). A review of clinical, paraclinical, pathological and evolutionary data was performed in all cases. Results: These were 9 female and 16 male, with an average age of 9 years. The average diagnosis time was 7 months. The main clinical presentation was abdominal mass. The main tumour size was 7,15 cm. 7 tumours were in upper limbs and 18 were in lower limbs. MRI was an essential exam for the diagnosis. There were 8 Ewing sarcoma/PNET (32%), 5 rhabdomyosarcoma (20%), 3 fibrosarcoma (12%), 2 dermatofibrosarcoma protuberans (8%), one inflammatory fibroblastic sarcoma (4%), one low grade fibromyxoid sarcoma (4%), one kaposi sarcoma (4%) and one myxoid liposarcoma (4%). Treatment is a combination of chemotherapy, surgery, and radiation. 5 patients were dead and 20 are still alive. Conclusion: Evaluation of paediatric soft-tissue tumours can be challenging. To formulate a differential diagnosis and, ultimately, diagnose a presenting lesion, the clinician should have an organised and systematic approach to the evaluation. Biopsy is a relevant and indolent exam for the diagnosis. Sarcomas represent the most common paediatric soft tissue cancers. To optimize their management and survival, patients should be treated at specialised centres to provide appropriate therapy and follow-up. PS-06-002 The role of preeclamptic stem villi obliterative angiopathy in the prognosis of newborn status O. Voronova*, L. Mikhaleva *PHI Clinical Hospital RZhD-Medicine, Rostov-on-Don, Russia Background & objectives: The prevention of ischemic changes in the placenta, where obliterative angiopathy of the villus vessels plays a leading role, requires the development of an objective prognosis tool. 70 placentas from women with preeclampsia of varying severity, 20 from healthy women. Methods: Morphometry was carried out using the Leica Applica- tion Suite module, Leica DM4000B. Micromorphometric indicators were determined: the area of the stem villi, the area of the lumen of the arterioles; diameters and areas of arterioles, including their wall thickness; measurements were made in 20 stem villi, the arte- riole obliteration degree was calculated according to the coefficient Ксо = Sат\Sа. Results: Foetal distress manifestation in preeclampsia depends on the severity of obliterative angiopathy. The nor- mal significance of the obliteration coefficient for arteri- oles1-2 the order of stem villi was 1.18-1.34, for the 3rd -1.19-1.37. With an increase in the obliteration coefficient of arterioles of the 1st and 2nd order of villi more than 1.34, and of the 3rd order more than 1.37, the frequency of chronic intrauterine hypoxia increased to 61.0%and 59.4%, respec- tively. The increase of this indicator in the combination of preeclampsia with extragenital pathology over 1.89 for villi of 1-2orders and 1.92 of 3rd was accompanied by the addition of an increase in intrauterine growth restriction to 31.3% and 29.6%, respective. Conclusion: The coefficient of arteriole obliteration is directly proportional to the incidence of chronic intrauterine hypoxia. When the placental villi arteriole obliteration coefficient exceeds critical value, the frequency of chronic intrauterine hypoxia and intrauterine growth restriction occurring in combination increases significantly. The significance of obliterative angiopathy in preeclamptic placentas in the functional state of the foetus and newborn was confirmed, and a prognostic model was created to calculate the probability of its occurrence. PS-06-003 Immunohistochemical characteristics of the vessels of the sup- porting villi of the placenta during preeclampsia O. Voronova*, L. Mikhaleva *PHI Clinical Hospital RZhD-Medicine, Rostov-on-Don, Russia Background & objectives: Morphological changes in the ves- sels in preeclampsia are not sufficiently reflected in the literature, especially for the stem villi and their branches. There are no clear morphological criteria for assessing the severity of hypoxia of a newborn. Methods: Studied 70 placentas from women with preeclampsia of varying severity, 20 placentas from healthy women. A macro- and microscopic examination of the placenta was carried out according to the generally accepted method. Immunohistochemical markers were used: CD34 (clone QBEnd\10), VEGF-A, eNOS. The level of expression of immunohistochemical markers was assessed in points: 0-no reaction, 1-weak reaction, 2-moderate reaction, 3-pro- nounced reaction. Results: Immunohistochemical markers detailed the cells producing these factors in the vessels and stroma of supporting villi. Using the CD34 marker, hyperplasia and desquamation of endotheliocytes were revealed with a pronounced formation of reticulate structures in arterioles (placental endotheliosis) and its "palisade" location in venules. A decrease in the expression of eNOS and VEGF-A was clearly accompanied by the presence of rheological disorders in the vascular bed, there was a progression of collagenization of the supporting villi stroma with the formation of perivascular sleeves and obliteration of the lumen of their vessels with signs of reduction of the paravascular bed. Conclusion: Morphological changes in the supporting villi are most pronounced in pregnancy complicated by preeclampsia. The lack of conditions for the implementation of compensatory reactions at the tissue level in the presence of preeclampsia exacerbates the severity of placental insufficiency, the development of obliterative angiopathy of the vessels of the stem villi, a decrease in blood flow in the capillaries of the terminal villi, which significantly worsens the prognosis for foetal development, increases the risk of adverse perinatal outcomes. PS-06-004 Foetal autopsy: causes of foetal death L. Simic*, J. Jevtic, M. Jovanovic, M. Ninkovic, J. Sopta *University of Belgrade, Faculty of Medicine, Institute of Pathol- ogy, Belgrade, Serbia Background & objectives: Perinatal mortality remains globally unacceptably high with up to three million stillbirth every year. Intrauterine foetal death and stillbirth are crucial part of perinatal mortality. Autopsy, correlated with clinical data, remains the “gold standard” for identifying causes of foetal death. Methods: A cross-sectional study, during the 2018 year, was per- formed by reviewing autopsy reports from the Institute of Pathol- ogy, Faculty of Medicine University of Belgrade. It was 1171 S89