ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 its branches. Clinical symptoms include chronic pancreatitis, weight loss, diabetes mellitus, and jaundice. The differential diagnoses of IPMNs include other pancreatic intraductal neoplasms, mucinous cystic neoplasms, and retention cysts. IPMNs without an invasive carcinoma are often curable. The prognosis for IPMNs with invasive carcinoma is significantly worse E-PS-07-031 Undifferentiated embryonal sarcoma of the liver (UESL), aris- ing in mesenchymal hamartoma: report of two adult cases N.R. Halepliler*, Z.B. Erdem, İ.M. Abdullahi, H. Kalaça, B. Yılmaz Özgüven, N. Dursun Kepkep *Basaksehir Cam ve Sakura City Hospital, Turkey Background & objectives: Embryonal sarcoma of the liver is a malignant neoplasm, composed of heterogeneous undifferentiated mesenchymal cells. About 50% of cases occur in children between 6 and 10 years of age and rarely occurs in adults. It occasionally arises in mesenchymal hamartoma. Methods: CASE 1:19-years-old male presented with abdominal pain and weight loss. Examinations revealed elevated liver enzymes and a cystic liver mass measuring 14 cm. CASE 2:33-years-old male patient with a history of surgery for hydatid cyst of liver one year ago, presented with recurrence of complaints. Imaging studies showed heterogeneously contrasting, lobulated solid 16 cm tumour on the right liver lobe. Results: Right hepatectomy was performed on both patients. On gross examination: first patient had 13.5x9x8.5 cm solid & mul- ticystic, partly oedematous tumoral lesion; second patient had 16.5x9.5x13 cm solid, lobulated tumour with extensive necrosis. On histopathologic examination, cellular component was composed of medium to large spindled or stellate cells with marked nuclear pleomorphism. Occasional PAS positive eosinophilic hyaline glob- ules were seen. With extensive sampling and serial sections, focal areas compatible with mesenchymal hamartoma were found in both tumours. Immunohistochemically, tumour cells were vimentin, CD56, BCL2, pancytokeratin and alpha-1-antitrypsin positive. As a result of morphological and histopathological findings, both cases were reported as "Undifferentiated Embryonal Sarcoma associated with mesenchymal hamartoma”. Conclusion: UESL is a challenging diagnosis. Due to the rar- ity of UESL in adults, these patients are often misdiagnosed as hepatic abscess, haemorrhagic cystic tumour, or hydatid cyst, as in the second case. It should always be included in the dif- ferential diagnoses of large liver masses, regardless of patient age. In addition, sampling and microscopic examination are very important as it can be associated with mesenchymal hamartoma. E-PS-08 | E-Posters Endocrine Pathology E-PS-08-001 Case report: secondary paraneoplastic hyperparathyroidism with brown tumour of the femur D. Proca* *Temple University, USA Background & objectives: The diagnosis of neuroendocrine tumour (NET) has serious implications concerning treatment and prognosis. In addition, paraneoplastic hyperthyroidism should always be considered in the differential diagnosis in a severely symptomatic patient with no evidence of abnormality in the parathyroid glands. Methods: We describe a 39-year-old female with 2 weeks right leg pain preventing her from ambulating; on imaging she had a 10 cm lytic lesion of femur and associated pathologic fracture. The patient presented with a 6 month-long history of nausea, vomiting, and weight loss. At admission, she endorsed signifi- cant polyuria, polydipsia, chronic abdominal pain, constipation, reflux and notable memory difficulties. Results: Lab investigations showed hypercalcemia (13.1 mg/ dl) and extremely elevated PTH (>2000 pg/ml). The differen- tial diagnosis included primary hyperparathyroidism, parathy- roid carcinoma, or ectopic PTH production. Additional imaging studies revealed a large lytic lesion in the femoral metaphysis and a well-circumscribed homogenous nodule in the right lower lobe. A lung biopsy was done and showed a well-differentiated neuroendocrine neoplasm, while a bone biopsy was suggestive of brown tumour. The profile suggested a well differentiated neuroendocrine tumour, grade 2 (4.0 cm greatest dimension) with focal necrosis. The histology and immunohistochemical features were consistent with atypical carcinoid, which was focally posi- tive with Chromogranin, Synaptophysin and CD56. Conclusion: Actively hormone secreting NET have been described in the literature, but NET secreting PTH and causing secondary hyperparathyroidism with brown tumour of long bones are very rare; some of the more common paraneoplastic syndromes seen in lung tumours, especially in small cell carcinomas and adenocarcinomas, are: hypercalcemia, inappropriate ADH secretion, hyponatremia, ectopic Cushing’s syndrome, carcinoid syndrome, hypoglycemia. This is a rare and interesting case that required a multidisciplinary approach and illustrated the importance of correlating laboratory with imaging and histology, E-PS-08-002 Reclassification of papillary microcarcinoma (PMC) accord- ing to the “Porto proposal” criteria A. Dhaoui*, S. Ben Rejeb, D. Aloui, M. Aloui, A. Hachicha, H. Chouchen, S. Turki *Forces de securité interieure, Tunisia Background & objectives: PMC is a variant of papillary carcinoma that measures≤1cm with an excellent prognosis.Recently, a proposal has been advanced to use the designation of papillary mirotumour (pMT) for PMCs with no risk factors. In this study, we aimed to reclas- sify pMCs according to the Porto-proposal (Pp)criteria. Methods: We have retrospectively collected 29 cases of PMC diagnosed in our pathology department (2012-2022). Clinical and pathological parameters have been retrieved from pathological reports. They included: age, sex, discovery circumstance, loca- tion, size, subtype, presence of psammomas, presence of tumour capsule, tumour capsule invasion, angioinvasion, extension to thyroid pseudo-capsule, multifocality, other concurrent thyroid pathology and state of the patient. We have evaluated and reclas- sified all cases following the Pp. We have briefly compared the clinical outcomes in both groups. Results: Mean age of patients was 46, 6-years-old (17-67) with a female predominance (sex ratio=2,2) .23 cases of PMC were incidentally discovered during lobectomy for benign conditions (9 cases), for PC of the ipsilateral or contralateral lobe (14 cases). In 6 cases, TIRADSV-thyroid nodule was discovered during ultrasound-imaging. The mean size of the tumour was 5,2mm. Multifocality was observed in 5 cases. The histological variant was follicular(25cases), conventional papillary(3cases) and tall cell (one case). A tumour capsule was present in 7cases and showed features of invasion in 4cases.Minimal thyroid S248