ECP 2023 Abstracts

S32 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Methods: All borderline or malignant ovarian tumours diagnosed in paediatric patients (under 18 years old) and treated at IPOLFG between 2000 and 2021 were retrieved. Clinical data was collected, and all his- tological slides were reviewed. Pre-diagnostic clinical data was missing in two patients and follow-up data was missing in another two patients who were excluded from the series. Results: A total of 52 patients aged 2-17 years old were included (median 12 years; follow-up mean: 88.3 months). Most (77%) had FIGO stage I disease. Two girls had DICER1 syndrome (4%) and another 2 had Turner syndrome (4%). The most common neoplasms were germ cell tumours (GCT)(52%) followed by sex cord-stromal tumours (SCST) (37%), with immature teratomas (n=12) and juvenile granulosa cell tumour(n=14), the most frequent. SCST and GCT were most frequent below the age of 10 and in the 10-14 age group, respectively. Three malignant and three borderline epithelial neoplasmwere diagnosed (11.5%), with only one borderline diag- nosed under 10 years of age. Seven patients developed disease recurrence/ persistence. Two patients died (recurrent juvenile granulosa cell tumour; unrelated cause). Conclusion: Irrespective of histological type, most patients in our series had an excellent prognosis. Tumour-predisposing syndromes are frequent in this age group (8%). Epithelial malignant neoplasms can occur in this age group and be exceptionally diagnosed below the age of 10. OFP-08-008 From morphology to genetics in syndromic craniosynostosis: two cases of a rare diagnosis in foetal autopsy J. Vaz Silva*, C. Mora, A. Costa Braga *Pathology Department, Portuguese Oncology Institute of Porto (IPO- Porto), School of Medicine, University of Minho, Braga, Portugal Background & objectives: Disruption of embryological craniofacial differentiation leads to a variety of craniofacial abnormalities. Cranio- synostosis occurs most commonly as an isolated event. However, when it involves multi-sutures and/or arises in a set of associated anomalies, a syndromic craniosynostosis should be suspected. Methods: Syndromic craniosynostoses are rare conditions, with the incidence varying between 1:25,000-1:100,000 live births. We describe two autopsy cases of foetuses presenting with craniosyn- ostosis and multiple other malformations associated, which were suspicious of a syndromic context. Results: Regarding the autopsies, both foetuses presented with bilat- eral coronal craniosynostosis, conditioning craniofacial changes, as well as with syndactyly of both hands and feet, hypoplasia of nasal bones, and intestinal malrotation. Additional malformations were detected, namely cardiovascular malformations (interventricular sep- tal defect; persistent left superior vena cava), central nervous system anomalies (corpus callosum and vermis hypoplasia, anomalous gyra- tion) and additional craniofacial abnormalities. Due to the presence of multi-sutures craniosynostosis along with addi- tional foetal malformations, the possibility of a syndromic context was raised, and genetic counselling was advised. In one of the cases pre- sented, a pathological variant in FGFR2 was identified, consistent with Apert syndrome. Genetic counselling is ongoing in the other case. Conclusion: Syndromic craniosynostoses are often sporadic, arising from de novo autosomal dominant mutations in FGFR and TWIST genes. Genetic counselling should be considered. We highlight the importance of craniosynostosis recognition during autopsy since it could prompt the diagnosis of these rare genetic syndromes, with pos- sible clinical implications for subsequent pregnancies. OFP-08-009 Discrepancies between clinical diagnosis and autopsy findings - 77 consecutive autopsies B. Sepodes*, V. Almeida, M.A. Cipriano *Centro Hospitalar e Universitário de Coimbra, Portugal Background & objectives: The clinical autopsy is a procedure in decline that guarantees medical care quality and assesses the global rate of health services. The studies pointed to discrepancies of around 30%. We aim to determine this rate at our hospital. Methods: We reviewed 77 autopsy reports performed at our hospital from 2017 to 2021 and evaluated diagnostic discrepancies between clinical diagnosis and autopsy findings. The major diagnostic errors were classified: Class I - misdiagnoses that directly impacted sur- vival; Class II - findings that would not have changed the course of the disease. Association with the length of hospitalization was also determined. Results: Of the 77 autopsy cases, 56% were male and 44% female, with a median age of 61 years. We identified discrepancies in 45,3% of the cases: 29,8% belonged to class I and 15,5% to class II. Pulmonary embolism and pneumonia were the most frequent misdiagnosis in class I. Occult neoplasias and infectious diseases played a significant role in class II. Post- operative complications were common but not always described in clinical reports. The rate of diagnostic discrepancy remained constant over time, and the length of hospitalization was inversely proportional to the discrep- ancy rate, particularly in the diagnosis of class I. Conclusion: Despite technological modernization, many erroneous/ incomplete diagnoses remain to identify. The results stress the impor- tance of the autopsy to clarify the cause of death accurately. The length of hospitalization suggests that lack of time for accurate diagnosis has an essential role. Our findings are consistent with the literature. We must consider the autopsy a potent research tool to understand the disease and face it as a crucial opportunity to improve clinical practice and medical training. OFP-08-010 COVID-19 postmortem evaluation by minimal invasive tissue sampling: histological findings, role of coinfections and genomic profiles P. De la Iglesia, A. Martinez, S. Segura, S. Villaroel, M. Garbarini, D. Alvarez Paggi, S. Esperante, J. Pollan, H. Michelangelo, M. Caballero* *Hospital Italiano de Buenos Aires, Argentina Background & objectives: Minimally invasive tissue sampling (MITS) can be used as an alternative to clinical autopsy. Our aim is to assess the histological findings, the prevalence of coinfections and the role of immune complexes in hospital deaths due to COVID-19 infection. Methods: We designed a cross-sectional study, based on MITS and medical record review of adults who died due to COVID19 at a ter- tiary hospital in Buenos Aires. Sampling was performed >6 hours after death. Lung, heart, bone marrow, liver, brain, cerebrospinal fluid and blood samples were obtained. RNA extraction and Nanostring was performed in tissue samples. Results: 17 patients were enrolled. Hypertension (11/17) and diabetes (8/17) were the most frequent comorbidities. Frequent histological findings were diffuse alveolar damage (DAD) (13/17), organizing pneumonia (8/17), capillaritis (14/17), liver steatosis (12/17), liver mild sinusoidal inflamma- tion (14/17) and hemophagocytosis 9/14. 10/17 patients had coinfection and 6 had histological evidence of bacterial coinfection in the lung (one lung abscess, 5 cases of exudative pneumonia). Patients had significantly higher titers of neutralizing antibodies than controls (p<0.05). RNA extraction was successfully performed, and gene expression profiles related to patients’ previous conditions were observed. Conclusion: MITS can be safely performed and can be a useful tool in assessing superimposed infections in the context of long hospitalizations both for histological and genomic analysis. Immune complexes do not seem to be relevant in COVID-19 related deaths. Histological findings of COVID 19 infection are similar to previously reported cases. RNA expression pro- files were related pre-existing conditions of patients. This project was funded by MITS Surveillance Alliance.