ECP 2023 Abstracts

S335 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 trophoblastic hyperplasia - features consistent with diffuse multifocal chorangiomatosis. Occasional sclerotic, avascular, and oedematous villi were noted. Conclusion: Chorangiomas have an incidence rate between 0.5% and 1%, and the diffuse multifocal form is even rarer (0.23%). This condition is associated with preeclampsia, twin gestation, intrauter- ine growth restriction, congenital malformations, and avascular villi, suggesting that this process may represent an abnormal response to hypoxia in very immature placentas. E-PS-19-024 Melanotic neuroectodermal tumour of infancy: report of three cases F. Rosa*, M.M. Lemos, R. Cabrera *Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal Background & objectives: Melanotic neuroectodermal tumour of infancy (MNTI) is a rare biphasic tumour of neuroectodermal origin, which typically occurs in the head and neck of young infants, with a slight male predilection. It has the potential to behave aggressively, recur and metastasize. Methods: We describe three cases of MNTI that were referred to our institution for treatment, two of them from developing countries, that illustrate the clinicopathological features, management and outcomes of this entity, with a review of the literature. Results: Case 1 refers to a 6-month-old boy with a recurrent 4 cm max- illary mass. Case 2 is a 7-month-old boy with a 4,5 cm paratesticular mass, and case 3 regards a 4-month-old boy with a 10 cm orbital mass. Microscopically, the tumours were comprised of small neuroblast-like cells and larger melanin-producing epithelial cells in a fibrocollagenous stroma. In the first two cases, complete surgical excision was achieved, via total maxillectomy and radical orchiectomy, respectively. At the age of two years, the patients were free of disease. In case 3 the lesion was unresectable and neoadjuvant chemotherapy was initiated, but the patient died from septic complications. Conclusion: These cases illustrate the classical clinicopathological fea- tures of MNTI and its possible outcomes. When completely resected, the patients were discharged from follow-up with no evidence of dis- ease. However, in the case with the larger skull inoperable lesion, the tumour resulted in the patient’s death. Early diagnosis and adequate resection, sometimes not available in developing countries, are key for an effective management, preventing recurrences and death. E-PS-19-025 Situs inversus totalis in combination with cardiomyopathy in the foetus: a case report I. Sertakov*, D. Tsimbalist, N. Alekseeva, A. Kvaratskheliya, A. Abasov, A. Filin *Voronezh State Medical University, Russia Background & objectives: Situs inversus totalis is a rare anomaly in the position of viscera, characterized by their mirrored inversion. The objectives of the study are studying the specificities of the location of viscera and analysis of the causes and frequency of anomalies. Methods: Patient U. 28 years old, admitted to the hospital with a gesta- tion period of 35 weeks, one foetus. In the first trimester she suffered from ARVI. Results: During ultrasound examination in a specialized centre situs viscerum inversus has been identified in foetus: In addition there were revealed a non-compact left ventricle of the heart, dilated cardiomyopathy, total failure of atrioventricular valves. The Genotek laboratory links the wrong position of organs with muta- tions of 41 genes. The patient had the cardiomyopathy with a mirror arrangement of organs, so we can assume the presence of a mutation in the ACTC1 gene. Conclusion: Situs inversus of internal organs can be diagnosed by ultrasound examination during prenatal period. The anomaly can be caused by the mutations in the genes responsible for the development of left-right asymmetry. There is a linkage between the position of the abdominal viscera and the heart’s position. E-PS-19-026 Clinicopathological evaluation of infantile fibrosarcoma: case series from a tertiary cancer centre D. Sharma*, M. Ramadwar, P. Panjwani, S. Qureshi, G. Chinnaswamy, M. Prasad, A. Baheti, V. Patil *Tata Memorial Hospital, Homi Bhabha National Institute, India Background & objectives: Infantile fibrosarcoma (IFS) is a rare malignant fibroblastic (rarely metastasizing) tumour commonly occur- ring in infancy. It is characterized by alterations leading to oncogenic activation of tyrosine kinase signalling. We aimed to characterize clinicopathological features of IFS cases at our centre. Methods: Retrospective analysis of 14 patients diagnosed with IFS in our department was performed over 7 years. Clinical and demo- graphic details, including treatment and follow-up information of patients, were gathered from the electronic medical records of our hospital. Available pathological data, including histological, immu- nohistochemical, and molecular characteristics were reviewed. Fluo- rescence in-situ hybridization (FISH) for NTRK1/2/3 alterations was performed in 4 cases. Results: All 14 patients were diagnosed within their first quinquen- nium (median age: 4 months). Three were congenital and 9 were diagnosed in infancy. Male to female ratio was 3.67:1. Microscopi- cally, cellular tumours with monomorphic spindled cells and numer- ous mitoses were the most consistent finding. Pan-TRK immuno- histochemistry (IHC) was diffusely positive in 4 of 4 cases with differential antigen localisation. FISH for NTRK gene rearrangement was positive in 3 of 4 cases. Six patients received neoadjuvant chemotherapy. Twelve patients underwent surgery. Adjuvant chemotherapy/radiotherapy was given to 4 patients. One patient developed bilateral lung metastases. All patients were alive with no evidence of disease at the last follow-up (range 1 to 44 months). Conclusion: IFS is a rare and frequently misdiagnosed malignant tumour that portends an overall good prognosis. Diagnosis is gener- ally based on the age of onset, clinical presentation, histologic features, and/or driver molecular aberrations. Lack of NTRK alterations by IHC/ FISH does not rule out a diagnosis of IFS. Neoadjuvant therapy with NTRK inhibitors is purported to alter the prognosis and surgical man- agement of patients with advanced or inoperable diseases. Awareness of the classic morphology and localization patterns of pan-TRK IHC is essential. E-PS-19-027 Placental foetal vascular malperfusion in congenital diaphragmatic hernia J. Stanek* *Division of Pathology, Cincinnati Children’s Hospital, USA Background & objectives: Congenital diaphragmatic hernia (CDH) is a severe, potentially treatable foetal malformation. The in-utero or intrapartum treatment success can be impacted by poor placental func- tion which has not been studied yet. This analysis aims to analyse placental pathology results in CDH. Methods: Frequencies of 24 independent clinical and 48 placental variables were statistically compared. Slides from 103 CDH pla- centas (Group 1), and from 133 clinical umbilical cord (UC) com- promise/anatomical UC abnormalities placentas, but without CDH