ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 barely noticed in the renal cortex. Comparative NGS analysis of both metastatic and primary foci were planned. Conclusion: Present case was interesting in different aspects. Unusual presentation posed a diagnostic pitfall. Despite of the metastatic foci forming a large mass with aggressive histologi- cal features, primary tumour foci were innocent, with milimetric, hardly detected nodules, low-grade histological features. Another striking feature was that these millimetric renal nodules showed different RCC types. We shared this case to raise awareness about this very rare presentation of RCC and to emphasize the importance of extensive sampling of the renal parenchyma when required. E-PS-24-051 Metastasis of renal clear cell carcinoma to contralateral ure- ter twenty years later after radical nephrectomy: a challenging diagnosis Y. Fejji*, W. Majdoub, A. Baccouche, M. Krifa, S. Mestiri, O. Belkacem, A. Bdioui, S. Hmissa *Department of Pathology, Farhat Hached University Hospital, Sousse, Tunisia Background & objectives: Metachronous metastasis of renal cell car- cinoma (RCC) to the contralateral ureter is extremely rare. We report a rare case of RCC metastasized to the contralateral ureter twenty years later and highlight the clinicopathological features of this rare presentation. Methods: A 58-year-old man with a history of a right radical nephrectomy for clear RCC 20 years ago and lost to follow-up presented an obstructive renal failure. Results: MRI shows a left tumour of the upper ureter. The patient underwent a radical left nephroureterectomy. On gross examina- tion, the upper ureter contained a white nodule extending over 1 cm with foci of haemorrhagic changes. The microscopic exami- nation shows compact nests and sheets of cells with clear cyto- plasm and distinct membrane growing beneath the urothelium and limited to the muscular propria of the ureter consistent with a metastasis of a clear RCC. Immunohistochemistry confirmed the diagnosis of contralateral metastasis of clear cell renal car- cinoma grade 2 of the ISUP grading system. Tumour cells were positive for CD10, EMA, and vimentin and negative for AMACR and CK7. Conclusion: Although clear RCC can metastasize to any location within the body, involvement of the contralateral ureter is very rare. This unusual diagnosis should be considered in any patient after treatment for RCC. Clear cell RCC has a worse prognosis than papillary or chromophobe RCCs, when matched for stage, and is more likely to present at an advanced stage or with existing metastases E-PS-24-052 Primary small cell carcinoma of the kidney: a rare case report S. Mabrouk*, T. Tlili, S. Yacoub, A. Ben Abdelkader, B. Sriha, M. Mokni *Department of pathology, Farhat Hached university hospital, Tunisia Background & objectives: Small cell carcinoma (SCC) is most com- monly seen in the lung, but rare cases of extrapulmonary sites have also been reported. Primary SCC of the kidney is an extremely rare neoplasm representing < 1% of renal neoplasms. Methods: A 27-year-old women without any previous disease, presented with a history of right lumbar abdominal pain for 2 months. A computed tomography scan of the abdomen revealed an ill-defined, large heterogeneous tumour in the upper pole of the left kidney, measuring 14,7cm and infiltrating the perirenal tissue. The patient underwent a left radical nephrectomy. Results: Gross pathological examination of the surgical specimen showed a large mass measuring 10 cm. Cut sections were brownish with necrotic areas. The renal capsule was intact. On Histologic examination, the tumour was composed predominantly of nested growth pattern with ribbons associated with extensive necrosis areas. These nests are surrounded by delicate connective tracts in a neuroendocrine-like pattern. The tumour cells were small with indistinct cell borders, scant cytoplasm, hyperchromatic nuclei with fine granular chromatin, and high mitotic activity. Immunohistochemical stains revealed that the tumour cells were strongly positive for CD56. The ki67 index was 60%. The tumour was staged as pT2a. Conclusion: SCC of the kidney is a high neuroendocrine neoplasm with aggressive behaviour and a tendency to develop early nodal and disseminated metastatic disease. It is an extremely rare neo- plasm, fewer than 60 cases have been reported in the literature. The diagnosis of a SCC is histologic and immunohistochemical. SCC is mainly misdiagnosed as other small round cell tumours. However, it is much more important always to rule out the exist- ence of a primary lung tumour metastatic to the kidney. E-PS-24-053 The Prevalence of CHEK 1 and CHEK 2 mutations in prostate cancer in Jordan population: a retrospective cohort study M. Alorjani*, S. Al Bashir, M. Al Zoubi *King Abdullah University Hospital, Jordan University of Science and Technology, Jordan Background & objectives: Prostate cancer (PCa) is one of the most common types of male cancers. This study aimed to investigate the occurrence of variations in mammalian checkpoint kinase 1/2 (CHEK1/ CHEK2) genes as key signal transducers inside the genomic integrity checkpoints in PCa. Methods: FFPE-PCa specimens of radical prostatectomies from 74 Jordanian patients were subjected to DNA extraction, polymerase chain reactions and Sanger sequencing to screen the mutations in selected exons of CHEK1 and CHEK2 tumour suppressor genes. Results: The mean age of the study population was 72 years. The mean of the PSA was 60 ug/L. The analysis of the CHEK1 and CHEK2 genes showed the presence of two point mutations in CHEK1 and CHEK2 genes (2/74, 2.8%). Specifically, F281L (T/C) (1.4%) homologous missense point mutation in the CHEK2 gene and c.564A>AT (188 P>P/P) (1.4%) silent mutation in exon 6 (kinase domain) of CHEK1 gene. However, the 1100delC mutation was not detected in the studied PCa samples. Conclusion: We found, and in line with previous studies, lack of association between CHEK1 mutations and PCa development. The presence of 1.4% of mutation in CHEK2 in our results supported the possible role of genetic variants in this gene and the develop- ment of PCa. Further studies are needed with larger cohorts to shed more light on these findings and to reveal the genetic predisposi- tion of the CHEK2 gene in the development of PCa in Jordan and perform screening of more exons. E-Posters | One-Day Molecular Pathology Diagnostics Symposium E-PS-MD-01 | E-Posters MD Symposium S363