ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Results: Histology showed malignant epithelioid cells with eosinophilic cytoplasm and moderate nuclear pleomorphism within a myxohyaline stroma. No mitotic figures or necrosis were present. Tumour cells expressed positivity for vascular markers (CD 34, CD31 and Factor VIII) and were negative for cytokeratins. Both WWTR1-CAMTA1 and YAP-TFE3 gene fusions are characteristics of this neoplasm. WWTR1-CAMTA1 gene fusion, resulting from a t(1;3)(p36;q25) translocation, is found in as many as 90% of cases. However, this tumour did not express these molecular alterations. The patient died in the following month of the diagnosis from terminal hepatic insufficiency. Conclusion: Hepatic epithelioid hemangioendothelioma is a rare tumour with immunoreactivity for keratins in many cases, poten- tially leading to confusion with carcinomas. The differential diag- nosis are metastatic or primary carcinomas and angiosarcoma. The latter is the most common primary malignant liver mesenchymal tumour in adults, and therefore, it is important for pathologists to be familiar with the immunohistopathological features of this hepatic entity. E-PS-07-014 A rare case of primary signet ring ampullary carcinoma A. Vilaia*, D. Raduta, L. Nichita, A. Voiosu, C. Popp *Colentina Clinical Hospital, Romania Background & objectives: Signet-ring cell subtype of ampullary car- cinoma is a rare occurrence with only than 49 cases reported in the literature. We present a case of a 68-year-old woman diagnosed with signet-ring cell ampullary carcinoma. Methods: 68-year-old woman complaining of chronic upper abdominal pain diagnosed with duodenal ulcer after mul- tiple endoscopic examination, presented to the emergency room with worsening of abdominal pain and sudden onset of jaundice. A CT scan was performed describing an ampullary lesion suggestive for a benign process, with no secondary lesions present. Results: The patient was transferred to our gastroenterology depart- ment and underwent an endoscopic retrograde cholangiopancreatog- raphy demonstrating occlusion of the common bile duct by a large, ulcerated lesion of the ampulla of Vater. Multiple biopsy fragments were taken from the affected area. The histopathologic examination revealed an ulcerated malignant proliferation of discohesive cells with signet-ring features, infiltrating the submucosa and expanding the lam- ina propria and villi. The diagnosis was supported by the special stains and immunohistochemistry markers performed. On small superficially obtained samples or ulcerated biopsy fragments, in the absence of clini- cal suspicion of a malignant proliferation, the diagnosis can be easily missed in the early stages. Conclusion: Signet-ring cell ampullary carcinoma is a rare entity and it may be difficult to diagnose. The patients usually present with jaundice and some of them with abdominal pain and it usually presents as an expansive ulcerated lesion with malignant features but there are cases when the endoscopic or CT aspects may not suggest a malignant process. Literature studies show that extensive sampling and biopsy fragments obtained from the depth of the lesion are needed for accurate microscopic diagnosis. E-PS-07-015 Pancreatic carcinoma: primary or metastatic? A case report E. Souka*, G. Galanopoulos, G. Stanc, N. Novkovic, K. Manoloudaki *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: Pancreatic metastases are rare with reported incidence 1.6% to 11% in autopsy studies. We report a rare case of renal cell carcinoma (RCC) metastatic to the pancreas, clini- cally suspected as a new primary tumour and a brief literature review. Methods: A 78-year-old female with a prior radical nephrectomy in 2002 for renal cell carcinoma was consulted for atypical abdomi- nal pain. CT-imaging showed a multilobulated mass measuring 4.5cm in greatest diameter at the pancreatic tail. A distal pancrea- tectomy was performed. Results: On microscopic examination the tumour was composed of clear cells with distinct membrane and pronounced nucleolus arranged in a solid and alveolar pattern. There were extensive areas of necrosis. Immunohistochemical examination revealed a [CKAE1/AE3(+), Cam5.2(+), EMA(+), Vimentin(+), CD10(+), RCC weekly (+), CK7(-), CD117(-), Chromoganin A(-), Synaptophysin(-)] phenotype. The morphological and immunohistochemical findings were consistent with metastatic clear cell renal carcinoma, in agreement with the past medical history. Conclusion: Among the metastasis to the pancreas, renal cell carcinoma is the most common. Despite this fact the clinical and radiological differential diagnosis of the metastasis remains a challenge. Histological examination is paramount for the accurate diagnosis. E-PS-07-016 Collision of low-grade hepatocellular carcinoma and low- grade chondrosarcoma A. Montasser*, S. E Anis, E. A Ishak *Department of Pathology, Theodor Bilharz Research Institute, Egypt Background & objectives: Collision tumours of the liver are rare. The commonest variant is collision of hepatocellular carcinoma (HCC) and cholangiocarcinoma. Chondroid differentiation may occur in sarcoma- toid HCCs which are high grade tumours. We report the collision of low-grade HCC and low-grade chondrosarcoma. Methods: A 65-years-old man with liver cirrhosis and history of treated viral C hepatitis presented with hepatic focal lesion (4x4.3cm) in segment VIII with elevated alpha-feto protein (AFP) and portal vein thrombosis. Patient started Sorafenib therapy and lesion pursued a stationary course for 18 months, with drop of AFP and recanalization of portal vein. Right hepatectomy was done. Results: The received surgical specimen revealed two adjacent nodules of tumour with well demarcated borders on a background of micronodular cirrhosis. Histologically, one tumour consisted of mildly pleomorphic polygonal hepatocytes arranged in thick trabecular and pseudoacinar patterns. The other tumour showed mildly pleomorphic malignant chondrocytes in lacunae embedded in chondroid stroma. Immunohistochemicially, the epithelial tumour was positive for HepPar-1, Glypican-3, and Arginase-1 confirming hepatocellular nature, while the mesenchymal tumour was positive for S100 and negative for epithelial markers. Molecular analysis is being performed. Post-operative 18F-fluorodeoxyglucose (FDG) PET/CT revealed clear operative bed with no FDG avid skeletal or soft tissue lesions. Six-months post-operative, the patient is event-free. Conclusion: The presence of chondroid matrix in HCC is not conclusive to high-grade sarcomatoid tumours, as collision of HCC and chondrosarcoma exists. Collision tumours of the liver are extremely rare and should always be reported and molecular S243