ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Methods: Transurethral resection of prostate was done and covne- tial biopsy with Hematoxylin Eosin was performed accompanied with immunohistochemistry to make the differential diagnosis. Review of English literature for the Primary Urothelial Carcinoma of the Prostate. Results: In this case report we present a 62 years old male, diag- nosed with primary urothelial carcinoma of the prostate. The patient was diagnosed with hyperplasia of the prostate before 4 years. The levels of PSA are normal. Symptoms worsened 6 months ago with haematuria, pain, frequent urination. Digital rectal exami- nation revealed that the prostate is enlarged and hard in the left lobe. The transurethral prostatic resection was performed and after the histopathologic examination together with immunohistochem- istry the patient was diagnosed with primary urothelial carcinoma of the prostate. Conclusion: Primary urothelial carcinoma of the prostate is a very rare tumour with a poor prognosis. In this way an early diagnosis and differential diagnosis is very important and should be taken in consideration in cases of worsening symptoms in a patient suffering with dysuria and with a firm prostate. E-PS-24-033 Papillary renal neoplasm with reverse polarity: an emerging entity A. Fitouri*, M.A. Bani, A. Valent, E. Rouleau, J. Scoazec, Z. Merabet *Pathology Department, Salah Azaiez Institute, Tunis, Tunisia/ Research Laboratory LR21SP01, Tunis, Tunisia Background & objectives: Papillary renal cell neoplasm with reverse polarity (PRNRP) is a recently described entity of renal tumour with unique morphological, immunohistochemical and molecular features. The objective is to emphasize on its pathological characteristics. Methods: We report the case of a 40-year-old woman with an indolent renal nodule which was operated on by right partial nephrectomy. Gross examination revealed a 2 cm well limited tumour. Results: On microscopy, the tumour show papillary and tubulo- papillary architecture. Tumour cells were cubic and had predomi- nantly eosinophilic cytoplasm, round to oval nuclei with stippled to clumped chromatin, minimal nuclear pleomorphism, inconspicuous nucleoli, and very rare mitosis. Tumour cells showed expression of CK7, GATA3 and PAX8. There were no expression of CD10, P504S, CK20, TFE3 and FH. Expression of INI1 and SDHB was retained. New Generation sequencing showed a KRAS c.35G>T, p.Gly12Val mutation. SNParray showed loss of chromosomes 1, 7, 11, 13, 19 and 20. There were also segmental loss in 2p25-q23, 3p12-p11, 5q22-q35, 6q, 9p, 10p15-q21, 17q21-q27, 18p-q12 and segmental gains in 4p13-q35, 6p25-p21 and 15q11-q15.The final diagnosis was PRNRP. Conclusion: PRNRP is a recently described tumour, by Al-Obaidy et al in 2019, defined by a tubulo-papillary architecture, GATA3 positivity and the presence of KRAS mutations. Approximately, 100 cases of PRNRP have been reported on the literature and they all exhibit an indolent clinical behaviour. Thus, this entity must be more recognized by pathologists for a better clinical guidance. E-PS-24-034 Well differenciated neuroendocrine tumour of the kidney. Histological, immunohistochemical, molecular and electron microscopy, analysis of a single case in a universitary hospital M. De Uribe Viloria*, E. García Fernández, P. González-Peramato *Hospital Universitario La Paz, Spain Background & objectives: Well differenciated neuroendocrine tumour of the kidney (WDNETK) not related to urothelial carcinoma is an extremely rare entity with less than 100 reported cases worldwide. It occurs in the renal parenchyma and shows neuroendocrine differentia- tion based on morphology and immunohistochemistry. Methods: We reviewed our files from 1970 to April 2022 found- ing a single case of WDNETK. The diagnosis was achieved by using Hematoxilin-Eosin, immunohistochemical, molecular studies and electron microscopy. From the clinical history we obtained the age at diagnosis, symptomatology and radiological studies. Results: A 45 year old female with a renal mass first diagnosed in US after an acute renal colic. A radical nephroureterectomy wit h regional lymphadenectomy was per formed. The tumour showed organoid architecture, diffuse positivity for synaptophysin and CD56, focal for chromogranin A. GATA 3, TTF1, p63, PAX 8, CK7, CK 20 and cathepsine K were negative. The proliferation index (Ki 67) was close to 8% in hotspot areas. Necrosis and lymphovascular invasion were identified. TFE3 and TFB were non rearranged by FISH. Following histological, immunohistochemical and molecular analysis the diagnosis of well differenciated neuroendocrine tumour of renal parenchyma was achieved. Four lymph nodes had metastasis. Conclusion: WDNETK is an exceptionally rare entity and due to its rarity it poses both a diagnostic and therapeutic challenge. Its main prognostic factors are stage and Ki 67 proliferation index and both should be reported. According to WHO 2022 classification the threshold of 3% of Ki67 separates good from poor prognostic although there are no consensus to establish grades like in gastrointestinal well differentiated neuroendocrine tumours. E-PS-24-036 Changes of nerve density in prostate cancer L. Krivošíková*, P. Janega, P. Babál *Institute of Pathological Anatomy, Comenius University, Bra- tislava, Slovakia Background & objectives: Innervation and axonogenesis in prostate cancer might be a promising therapeutic target, prognostic marker, and replacement for reporting perineural invasion in small samples. We aimed to detect changes in nerve density in BPH, prostate cancer, and correlation with Gleason score. Methods: We used patient samples of prostate cancer (n=34), BPH (n=18), and autopsy prostate samples without pathological changes (n=36). For immunohistochemical detection of nerves and nerve proliferation, we used double-staining using antibodies against S100 and PCNA. The nerve area was measured by histomorphometry with colour deconvolution to extract S100 positivity. The proliferation of nerves was analysed quantitatively. Results: There was a significant decrease of nerve density in prostate cancer compared to normal prostate and BPH. We also found a non- significant decline of nerve density with an increasing Gleason score. There was higher nerve density in BPH than in normal prostate tissue, but the difference wasn’t significant. There were only isolated PCNA-positive cells in nerve fibres, mostly in benign hyperplasia. However, because of the sparse occurrence of these cells, we didn’t quantify them. Conclusion: We found a significant decrease of nerve density in prostate cancer without proof of axonogenesis. These findings are opposite to the results of other authors. However, almost all of the works are experimental, whereas there is a minimal amount of data about changes of the innervation of human S358