ECP 2023 Abstracts

S30 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Conclusion: Simultaneous evaluation of SATB2, CKAE1/AE3, and synaptophysin detects nodal metastatic MCC cells with the highest diagnostic sensitivity, independently of MCPyV status. We propose including them in the routine MCC sentinel lymph node biopsy/lym- phadenectomy protocol of histopathologic evaluation. This research was funded by a statutory subsidy by the Polish Ministry of Science and Higher Education as part of Wroclaw Medical Uni- versity’s grants SUBZ.A430.22.089 and SUBZ.A430.23.075 (records number in the Simple system) granted to Piotr Donizy. OFP-08 | Joint Oral Free Paper Session Paediatric and Perinatal Pathology / Autopsy Pathology OFP-08-001 CD34 immunostain increases the sensitivity of placental examina- tion for distal foetal vascular malperfusion in liveborn children J. Stanek* *Division of Pathology, Cincinnati Children’s Hospital, USA Background & objectives: Placental foetal vascular malperfusion (FVM) is associated with increased perinatal morbidity and mortality. This retrospective observational analysis was performed to compare the impact of large proximal vessel, remote distal villous, and recent FVM diagnosed by endothelial fragmentation by CD34 immunostaining. Methods: Clinical and placental phenotypes (expanded Amsterdam criteria) of 581 live births were compared: Group 1 73 cases without FVM, Group 2 220 cases with large vessel FVM without distal vessel changes, Group 3 132 cases with remote distal vessel FVM, Group 4 87 cases with recent FVM, and Group 5 69 cases with combined remote and recent features of FVM. Results: FVM was present in 88% of placentas from high-risk preg- nancy dominated by congenital anomalies. 43% of those were global (partial, large proximal vessel) FVM without distal villous changes, least commonly high-grade (13%), least commonly with complicated perinatal outcome (except for congenital anomalies (79%), and with least common other abnormal placental phenotypes, particularly mater- nal vascular malperfusion, chronic villitis and plasma cell deciduitis; however, large vessel FVM lesions were commonly associated with distal FVM. Remote distal villous FVM and particularly on-going FVM with temporal heterogeneity is statistically significantly asso- ciated with preterm births, preeclampsia, abnormal umbilical artery Dopplers, foetal growth restriction, highest caesarean section rate and high grade FVM overall. Conclusion: Lesions of global FVM feature relatively low sensitiv- ity for perinatal complications. Isolated recent distal villous (segmen- tal) FVM diagnosed by clustered endothelial fragmentation by CD34 immunostaining without avascular villi on hematoxylin-eosin (remote changes) does not feature significant perinatal morbidity/mortality either, likely because of its short duration. Remote FVM (long lasting), and particularly on-going lesions with temporal heterogeneity portend the most complicated perinatal outcome, low placental weight, post- uterine pattern of placental injury, villous infarction, chronic villitis, and are most frequently high grade. OFP-08-002 Histopathological findings in placentas and adverse perinatal out- comes from pregnant patients with autoimmune diseases A. Nadal*, A.S. Castellanos-Gutierrez, F. Figueras, G. Espinosa, L. Youssef, F. Crispi, M. Santana, N. Baños *Hospital Clinic, Spain Background & objectives: To describe the pattern of placental lesions in women with autoimmune diseases (AID) and correlate the placental findings with the occurrence of adverse perinatal outcomes (APO). Methods: 91 women with AID (42 SLE, 21 NC-OAPS, and 28 APS) and 91 controls were included. The perinatal outcomes and placental findings of pregnancies with AID (systemic lupus erythematosus [SLE], antiphos- pholipid syndrome [APS], and non-criteria obstetric APS [NC-OAPS]) and gestational-age matched healthy controls were analysed and classified according to the 2015 Redline - Classification of placental lesions. Results: Placental weights were significantly lower in NC-OAPS and APS groups compared to controls. 14.3% of placentas in the APS group was < 3rd percentile which was exceedingly higher than in other groups. Maternal malperfusion was significantly increased in APS (46.4%) compared to NC-OAPS (14.3%) and SLE (9.5%). Foetal vascular- stromal maldevelopment was significantly increased in NC-OAPS (19.1%) compared to controls (1.1%) and SLE (2.4%). APOs were more frequent in all AIDs compared to controls (3.3% vs 52.4-64.3%). Overall, both maternal (OR 6.8, 95%CI 2.1-22) and foetal-side (OR 4.1, 95%CI 1.3-13.5) lesions were associated with APO. Maternal malp- erfusion and developmental foetal vascular-stromal lesions were the lesions most strongly associated with APO. Conclusion: Pregnant women with SLE, APS, or NC-OAPS showed a different pattern of histopathological findings. Compared to controls, all AID conferred an increased risk of APO that was strongly associ- ated with placental maternal-side malperfusion and foetal-side malde- velopment vascular-stromal lesions. OFP-08-003 Sarcina colonization in three paediatric patients with delayed gastric emptying, and esophagitis with increased intraepithelial eosinophils (EIEo) C. Salgado*, Y. Hadjiyannis, S. Ali, Q. Wang, E.V. Zambrano Tola, M. Reyes Mugica *University of Pittsburgh, Pathology, USA Background & objectives: Sarcina organisms are rare, gram-positive, sugar fermenting cocci, identifiable by molecular testing or histomor- phologic examination. The pathologic potential and relevance of Sar- cina identification in gastrointestinal tract biopsies is ill-defined, but complications such as emphysematous gastritis, and gastric perforation are described. Methods: Following institutional review board approval, the cases were selected at Children’s hospital using retrospective search of the pathology archives (1/1/2020 to 4/1/2023). The original slides were reviewed by two pathologists (CMS and MRM); clinical information and image studies were obtained from electronic medical records. The presence of Sarcina was confirmed in three cases; their clinical and histological features were described. Results: Three boys (9, 11 and 16 years-old); two of them having developmental delay (one in the autism spectrum and the other with chronic epilepsy). All patients presented with variable degrees of abdominal pain and reflux-related symptoms (vomit/ regurgitation/ dyspepsia) associated with delayed gastric emptying. In one case, the Sarcina colonization was diagnosed after treatment of Helicobacter pylori gastritis with associated duodenal lesion/ obstruction. Histo- logically, all patients demonstrate variable reactive gastropathy and EIEo. Duodenal inflammatory changes were present in two cases. The bacteria arranged in tetrads or octets, consistent with the morphologic diagnosis of a Sarcina organism present in the surface of the oesopha- gus and stomach in all three cases. Conclusion: Previous reports of paediatric cases linking clinical symptoms with findings of Sarcina on histology are scant and rarely associated with EIEo. These three paediatric cases presented with pre- viously reported Sarcina-related symptoms including abdominal pain and vomiting. Because of the ubiquitous environmental presence of Sarcina, the clinical significance of this finding is not well character- ized, and the decision to treat, along with the chosen regimen, remain