ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 YAP1-TFE3 fused subtype. Immunohistochemistry also supported the YAP1-TFE3 fused variant, by CAMTA1 negativity and TFE3 positivity. First case had metastatic lesions on the C2-C3 vertebral level and multiple lesions on the liver in the MRI after 2 years of follow-up. The hepatic lesions were confirmed as HEHE by biopsy. He received medical oncological therapy. Two and a half years after the transplantation patient died of hepatic failure. Second case has no distant metastasis or recurrence after 3 months of follow-up. Conclusion: Hepatic epithelioid hemangioendothelioma with YAP1-TFE3 fusion is an extremely rare, recently described malig- nant vascular tumour. Awareness of this variant’s morphologic features are important during differential diagnosis and to avoid misclassification. E-PS-07-028 Adenomyoma of the ampullary region: a malignancy mimicker S. Frini*, S. Mestiri, O. Belkacem, A. Bdioui, A. Baccouche, S. Hmissa *Pathology Department, Sahloul University Hospital of Sousse, Tunisia Background & objectives: Adenomyoma and adenomyomatous hyperplasia in the gastrointestinal tract are commonly benign lesions, usually found in gallbladder. Rarely, they occur in the ampullary region and cause serious complications. Herein, we describe the clinico- pathological features of an adenomyoma of the Vater’s ampulla. Methods: A 61-year-old woman presented with obstructive jaundice and mild abdominal pain. Blood tests showed conjugated hyperbilirubinemia. Duodenoscopy revealed a bulging ampulla with normal overlaying mucosa. Radiological examinations reported no further extension. Endoscopic biopsy was inconclusive and couldn’t exclude malignancy. Seeing it was symptomatic and suspicious of malignancy, a cephalic pancreaticoduodenectomy was performed with uneventful post-operative course and follow-up. Results: Gross examination showed a 6mm, white, firm lesion of the ampullary wall. Histologically, it consisted of an admixture of benign epithelial and mesenchymal elements: proliferating benign glands of various size lined by columnar cells and separated by disorganized fibromuscular tissue. The overlying mucosa was unre- markable. Peripancreatic, hepatic pedicle’s and superior mesentery lymph nodes were free of tumour. The gallbladder, which was con- veyed with the surgical specimen, displayed chronic cholecystitis. Conclusion: Since the vast majority of ampullary adenomyomas present suspicious symptoms and mimic malignant tumours, its preliminary diagnosis could be very challenging. Due to the serious clinical implications of over-treating a benign lesion; a careful endoscopic, radiological and pathological assessment are mandatory in order to ensure an accurate pre-operative diagnosis, especially that these screening modalities are nowadays, more accurate to fulfill this purpose. E-PS-07-029 Liver solitary fibrous tumour with simple biliary cyst: a radio- logical and histological diagnostic challenge N. Ahmed, F. Falcinelli, F. Ratti, M. Colombo, C. Doglioni, F. Pedica* *Pathology Unit, IRCCS San Raffaele Scientific Institute-Vita- Salute San Raffaele University, Italy Background & objectives: Primitive solitary fibrous tumour of the liver is an extremely rare mesenchymal tumour with uncertain biological behaviour, only a few cases reported in the literature, no definite criteria of malignancy and whose preoperative diagnosis can be very challenging. Methods: We report the case of a 68-year-old man who presented with dyspepsia and had no history of previous neoplastic disease. Ultrasound, MRI and CT scan showed a mass forming lesion of 10 x 7,5 x 9,5 cm, partially cystic with a solid component of 5 x 6 cm, involving the IV hepatic segment, vascularized from the left hepatic artery. Results: At gross examination, a left hepatectomy showed a 11 x 8 x 10 cm neoplasm, mostly solid with a cystic part not communicating with the biliary tree. At microscopy, the solid part was made of storiform spindle cells organised in bundles, with focal myxoid and fibrotic changes, involving the peribiliary tissue, sparing the porto-biliary peduncle; focal ischaemic necrosis occurred. The cyst was covered by a biliary epithelium with pseudopyloric metaplasia. Neoplastic cells were strongly and diffusely immunoreactive for CD34, STAT6 and BCL2, negative for S100, CD117, DOG1, ERG, PR, inhibin, calretinin and WT1. The mitotic count was 4 mitoses/10 HPF and Ki67 was 15%. Lymph nodes were free of neoplasia. Conclusion: A diagnosis of primary hepatic solitary fibrous tumour adjacent to a simple biliary hepatic cyst was provided. No similar cases are reported in the literature. Since it is a very rare primitive liver neoplasm, no criteria are available for prognosis and therapy. We decided to apply the score proposed by Demicco and Colleagues (Modern Pathology 2017; 30,1433–1442) and the neoplasm was considered as an" intermediate risk" lesion. The patient is currently free of neoplasia, undergoing close follow up. E-PS-07-030 Invasive adenocarcinoma arising from an intraductal papillary mucinous neoplasm of the pancreas: a case report Y. Fejji*, S. Mestiri, A. Baccouche, S. Frini, S. Hmissa *Department of pathology, Farhat Hached University Hospital, Sousse, Tunisia Background & objectives: Intraductal papillary mucinous neoplasms (IPMNs) are mucin-producing cystic lesions that involve the pancreatic ductal system. A subset of IPMNs will progress to invasive carcinoma. This study aims to present a case of malignant transformation of an IPMN to better understand this entity Methods: We report a case of a 60-year-old female without past medical history who presented with signs of mixed pancreatic insufficiency: recent diabetes and steatorrhea associated with weight loss and anorexia. The radiological exploration concluded with a tissular lesion of the head of the pancreas with dilatation of the main and secondary pancreatic ducts. The patient under- went a cephalic pancreaticoduodenectomy. Results: On gross examination, serial sectioning showed an ill-limited whitish mass with a myxoid change, reaching the duodenum without infiltrating it. The tumour measured 8,5x 6,5cm. The Wirsung duct was dilated, containing a friable whitish material. Histology examination showed intestinal- type IPMN that involves both the main and the secondary ducts. The tumour contained also foci of invasive adeno- carcinoma, which were also found in the surgical sections, Lesions of chronic atrophic autoimmune pancreatitis were also found. The patient underwent a totalisation of its pan- createctomy and adjuvant chemotherapy was also indicated. Conclusion: IPMNs are rare and are characterized by a risk of malignant transformation. Histologically, IPMNs are divided into three subtypes: intestinal, gastric, and pancreaticobiliary. IPMNs can occur anywhere in the main pancreatic duct and/or S247