ECP 2023 Abstracts

S370 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 E-PS-24-013 Bilateral gonadoblastoma in a nine-year-old patient with ambigu- ous genitalia: a case presentation M.Y. Çelik*, S.B. Yolburun, G.Ö. Elpek, C.I. Bassorgun, B. Ünal *Akdeniz University Department of Pathology, Turkey Background & objectives: Most patients with gonadoblastoma pre- sent as neonates with ambiguous genitalia in the setting of a disorder of sexual development. Because of the rarity of bilateral gonadoblastoma, we present a nine-year-old patient with bilateral gonadolastoma appear on streak gonads. Methods: A 11-days-old patient presented to paediatric endocrinology clinic with ambiguous genitalia. Laboratory data showed that total testos- terone and 11- deoxycortisol was high. Chromosomal analysis reported as 46XY. hCG stimulation test resulted with increase in the ratio of tes- tosterone to DHT after hCG administration. After 9 years, USG scan showed that right testis was 9*7*3 mm and left testis was 10*8*2.5 mm. Results: Bilateral gonadectomy was carried out by paediatric surgeons. The encapsulated, soft, whitish grey, shiny materials was examined carefully. After total sampling, we observed round nests and cords composed of germ cells, small sex cord cells, and globoid deposits of hyaline basement membrane material in both gonadal materials. The germ cells that had large nuclei, prominent nucleoli and pale cytoplasm scattered between the sex cord cells that showed angulated nuclei with basement membrane material was seen microscopically. A few mito- sis were observed in some germ cells without atypia and necrosis. Germ cells were stained with PLAP, CD 117 while the stromal cells expressed inhibin, WT1. Conclusion: Given the potential for gonadoblastoma to transform into an invasive germ cell tumour, gonadectomy is recommended. On microscopic view, nested to corded arrangement of germ cells and sex cord cells with deposits of basement membrane material are essential diagnostic criterias whether immunohistochemical markers for germ cells and sex cord stromal cells applied or not. Also gonadoblastoma should be differentiated from sertoli cell nodules colonized by GCNIS, sex cord stromal tumour with entrapped germ cells for exact diagnosis in prepubertal cases. E-PS-24-014 Paraganglioma of urinary bladder: report of 4 cases E.E. Cetiner*, F. Çakalağaoğlu, F.H. Dilek, A. Akder Sari *Izmir Katip Celebi University, Ataturk Training and Research Hospi- tal, Department of Pathology, Turkey Background & objectives: Paragangliomas are extra-adrenal pheo- chromocytomas. Paraganglioma of urinary bladder is very rare. They are rarely malignant. Typical symptoms are catecholamine secretion associated such as micturition periods. However, it may be asympto- matic and can be diagnosed incidentally. Methods: This is a retrospective study that includes four bladder paraganglioma cases diagnosed between the years 2008-2022 in our hospital. Results: All cases were female. Median age was 46,5 (between 34-57) years old. Three patient was diagnosed incidentally, and one presented with incontinence and abdominal pain. Median size of tumours was 3,3 (between 2,8-4) cm. All patients were diagnosed by transurethral resec- tion one of which afterward underwent partial cystectomy. All tumours were positive for synaptophysin, chromogranin and GATA3. Pankeratin was negative. Succinate Dehydrogenase B(SDHB) was available in only one case which was intact. Proliferative index was low. Zellbal- len growth pattern which is typical for paragangliomas was either not present or not prominent. Follow up of two patients for six and twelve months were free of recurrence. Conclusion: Paraganglioma of urinary bladder is very rare. Features which might serve as clues for paraganglioma diagnosis such as typical clinical symptoms and characteristic Zellballen pattern are not always present, and the tumour cells express GATA3 which may mimic urothe- lial carcinoma. Therefore, awareness of this entity is upmost important to avoid misdiagnoses. E-PS-24-015 Traditional serrated adenoma of the bladder: a rare case originat- ing from urachal diverticulum A. Chikha*, F. Skenderi *Clinical Center of University of Sarajevo, Department of Pathology, Bosnia and Herzegovina Background & objectives: A 61-year- old female patient was hospi- talized due to haematuria. CT urography revealed polypoid tumour in the area of highly suspicious urachal diverticulum. During cystoure- throscopy, tumour were detected at the bladder dome and was partially removed by transurethral resection. Methods: Pathological examination revealed a complex villiform growth pattern with slit-like serrations and ectopic crypts. The tumour was lined by intestinal type epithelium, with cells exhibiting eosino- philic cytoplasm and pseudostratified elongated nuclei. Immunohis- tochemical analysis demonstrated positivity for CK7, CDX2, CD20 (partial), Ki-67 and beta-catenin in the ectopic crypts and at basis of the crypts, where displayed cytoplasmic and membranous positivity. Results: The epithelium showed mostly low-grade dysplasia, with focal high-grade dysplasia. These findings were consistent with a traditional serrated adenoma, an infrequent type of colonic serrated polyp that typically observed in the distal colon and accounts for less than 1% of colonic polyps. The adjacent mucosa of bladder exhibited signs of intestinal metaplasia. After transurethral resection and diagnosis of traditional serrated adenoma, residual tumour was resected by partial cystectomy. Conclusion: To date, only few cases of extra-gastrointestinal tradi- tional serrated adenoma has been previously reported. Our case verifies the rare occurrence of this type of adenoma in the bladder that may originate from intestinal metaplasia and in our case more likely from urachal diverticulum. E-PS-24-016 Grading of T1a clear cell renal cell carcinoma based on nodule size, tumour necrosis, and ISUP grade C. Choi*, M. Noh, S.S. Kim, E.C. Hwang *Chonnam National University Medical School, Republic of Korea Background & objectives: Although majority of T1a clear cell renal cell carcinomas (T1a-CRCC) reveal very good prognosis, a few cases show catastrophic prognosis. The purpose of this study is to stratify T1a-CRCC into prognostically accurate subgroups. Methods: T1a-CCRCC surgically treated and diagnosed in the pathol- ogy departments of CNUH and CNUHH between 2004 and 2019 were selected. They were 614 nodules from 611 patients. Multivariable logistic regression analysis was performed to find the factors associ- ated with cancer specific survival (CSS). They were graded based on nodule size, tumour necrosis, and ISUP grade. Results: Grading of T1a-CRCC based on nodule size, tumour necrosis, and ISUP grade was a better predictor of CSS (c-index 0.798) than that based on ISUP grade only (c-index 0.685). Group A (nodule ≤1.5 cm, without necrosis, and any ISUP grade) was 89 cases, group B (nod- ule 1.5-4.0 cm, without necrosis, ISUP grade 1 or 2) 416, and group C (nodule 1.5-4.0 cm, with necrosis and ISUP grade 2-4, or without necrosis and ISUP grade 3-4) 109. With a median follow-up of 69.8 months, 10-year CSS rate of group A was 100%. That of group B and C was 99.0% and 95.5%, respectively. Conclusion: We suggest a grading of T1a-CRCC based on nodule size, tumour necrosis, and ISUP grade.