ECP 2023 Abstracts

S204 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 understanding the mechanisms of this disorder is crucial for effec- tive treatment. Methods: Morphological changes of the enteric nervous system and the interstitial cells of Cajal were evaluated by immunohistochemi- cal staining in rectal biopsy samples from CIC patients (n=12) and compared with controls (n=4). The number of ganglion cells in the submucosa, the thickness of nerve fibres and the percentage of envelop- ment of myenteric ganglia by ICC was evaluated. Results: Our study found that patients with chronic constipation showed a non-significant decrease in colonic ganglion cells in the submucosa compared to the control group. Hypertrophic nerve fibres were absent in controls but were detected in 5 out of 12 CIC samples. In addition, there was a significantly lower percentage of ICC envelop- ment of myenteric ganglia in samples from patients with chronic con- stipation compared to controls. These findings suggest that there may be morphological changes in the enteric nervous system and interstitial Cajal cells that contribute to chronic constipation, although further research is needed to confirm this hypothesis. Conclusion: Emerging evidence suggests that abnormalities in the enteric nervous system and changes in the interstitial Cajal cells play a central role in the development of gut motility disorders. When the number of Cajal cells is reduced, pacemaker activity is impaired, and the loss of enteric ganglia and glial cells reduces nerve impulses to effector cells, leading to inefficient and uncoordinated function of the colon. Our study supports this multifactorial pathophysiology of colonic motility disorders. Funding: APVV 20-0243 and VEGA 1/0684/21 E-PS-06-044 A rare localization of alveolar soft part sarcoma – A report of two cases R. Jankovic*, S. Oprić, M. Denčić Fekete, M. Jovanović, M. Đuknić, J. Jevtic, L. Simic, M. Mihajlović, N. Šimšić, J. Sopta *Institute of Pathology, Medical Faculty, University of Belgrade, Serbia Background & objectives: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal tumour typically occurring in young patients, more frequently in females. ASPS in visceral organs usually represents a metastasis from primary ASPS in skeletal muscles. Methods: ASPS is characterized by a tumour-specific translocation which causes the fusion of the TEF3 with a ASPL gene (also known as ASPSCR1). Two patients were admitted to hospital due to symptoms of acute abdomen. Urgent surgery was performed, and tumour was detected in both cases. Results: In first patient (female, 47 years old) ileal tumour was detected intraoperatively, while in other patient (male, 67 years old) rectal tumour with perirectal infiltration were detected. In both cases perforation within tumour were noted. Histology showed well-defined nests of pleomorphic cells separated by delicate fibrovascular septae. Beside this feature, foci of pseudoalveolar pattern were seen. Both tumours were diffusely immu- nopositive for TFE3 and vimentin. Other immunostainings exclude other TFE3 positive tumours – PECOMA, TFE3 positive haemangioendothe- liomas and TFE3 positive renal cell carcinoma. FISH analysis was done using locus specific dual colour break-apart TFE3 (3’ and 5’) probe and rearrangement in the TFE3 gene was confirmed in both cases. Conclusion: Despite the fact that ASPS is rare mesenchymal tumour in visceral organs. it should be considered as possible diagnosis, espe- cially in cases with typical histological features and immunohistochem- ical profile. FISH analysis is mandatory for definitive ASPS diagnosis. E-PS-06-045 Acute measles gastritis: a rare case report J. Jevtic*, L. Simic, M. Đuknić, M. Korać, R. Jankovic *Institute of Pathology, Serbia Background & objectives: Due to availability of vaccines and timely vac- cination, measles virus infections are highly unusual in developed countries, except for rare, usually imported cases from unvaccinated communities. Methods: We report a case of a 35 years old male patient presented with fever, upper abdominal pain and vomiting with blood traces. Due to the aforementioned clinical presentation, the patient underwent upper endoscopy with biopsy sampling. Results: Pathological analysis showed surface defects lined by fibrin and neutrophils which was consistent with acute erosive gastritis. Individual foveolae were dilated filled with apoptotic debris and neu- trophils. Numerous mulberry-like multinucleated giant cells (Warthin Finkeldey) with Cowdry type A inclusions were present in foveolar and surface epithelium as well as in the stroma of lamina propria. Shortly after the endoscopy, the patient developed a rash, which raised suspicion of measles. Short anamnesis and insight into medical records showed that the patient has never been vaccinated for MMR vaccine. Conclusion: Serological analysis was positive for measles IgM antibodies and the patient was diagnosed with measles. After a few days, with symp- tomatic therapy, the patient fully recovered without any complication. E-PS-06-046 Demystifying ‘hyaline angiopathy’ of pulse granuloma in oral and extraoral surgical pathology- a case series of thirteen oral and five extraoral cases R. Kanthan*, F. Sperandio *University of Saskatchewan, Canada Background & objectives: ‘Giant cell hyaline angiopathy’ described in Pulse Granuloma (PG) occurs in lesions from the beginning [mouth] and ending (colonic) of the digestive tract. The aim of this study is to demystify this ‘hyaline angiopathy’ that is described in these lesions. Methods: A computer search of 135,972 consecutive surgical pathol- ogy cases with the diagnosis of ’pulse granuloma’ was undertaken. The histopathological slides together with their demographic data and clini- cal findings were reviewed. Congo Red, Masson trichrome, Periodic Acid-Schiff (PAS), CD31, ERG, D240, and CD34 were performed on a representative formalin-fixed paraffin-embedded tissue block for each case with appropriate positive and negative controls. Results: A total of 18 cases (thirteen oral and five extraoral) were identi- fied. These lesions occurred in children and adults ranging from 7-83 years with a male predominance in oral cases while the extraoral cases were all females. The majority of oral PGs were associated with an inflamed odontogenic cyst or non-healing extraction socket. The extraoral cases were seen in: Appendix [3]; Peritoneum [1] and cecum [1] associated with inflammation and perforation. Congo Red was negative in all cases. The wormy ‘hyaline angiopathy’ expressedMasson/PAS and had no expression of the angiolymphatic markers ERG, D240 or CD31 with the latter outlin- ing the surrounding vasculoinflammatory response of the pulse granuloma. Conclusion: Our study supports the etiopathogenesis of oral and gastro- intestinal PGs to reflect a granulomatous response triggered by the pres- ence of certain components in legumes/seeds. The consistent positivity for Masson and PAS with total lack of vascular immunostaining within these "wormy" structures proves there is no evidence of any ‘angiopathy’ in these granulomas and continued usage of this term is to be strongly discouraged. We propose these "wormy" structures represent a varied fibrocollagenous tissue response dependent on the legume/seed present. E-PS-06-047 A case of gastric adenocarcinoma with enteroblastic differentiation and carcinosarcomatous feature Y. Kim*, Y. Chun *National Health Insurance Service Ilsan Hospital, Republic of Korea Background & objectives: We present a rare case of gastric adeno- carcinoma with enteroblastic differentiation and massive lymph node