ECP 2023 Abstracts

S383 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 morphological aspect and the immnohistochemical profile led to a diag- nostic of a UC with trophoblastic differentiation. Conclusion: UC with trophoblastic differentiation is associated with high- grade UC, poor response to chemo- and radiotherapy, and a worse prognostic than the conventional variant. It is also related with a high risk of recurrence, progression, and death of patients. Therefore, the morphological recognition of this category of UC is important, in order to ensure an individualized therapeutic strategy and the best possible clinical outcome of the patient. E-PS-24-064 PIN-like carcinoma of the prostate, an incidental finding on a TURP – a case report M.C. Popelea*, C. Chibelean, I.G. Cocuz, A. Loghin *Pathology Department of Mures County Clinical Hospital, Romania Background & objectives: Prostatic intraepithelial neoplasia (PIN)- like carcinoma is an uncommon subtype of prostatic acinar adenocar- cinoma, composed of large glands lined by malignant pseudostratified columnar epithelium. Herein, we report a case of a patient clinically diagnosed with prostatic adenoma. Methods: A 59-year-old patient known with bladder lithiasis since 2016 and benign prostate hyperplasia diagnosed in 2019, presented in January 2023 at the Urology Department with urinary symptoms. The total serum prostate-specific antigen (PSA) was 1,61 ng/ml. Transure- thral resection of prostate (TURP) was performed, and the specimen was sent to our Pathology Department for histopathological diagnosis. Results: Microscopically, the prostatic tissue showed glandular and stromal hyperplasia. On only one fragment a tumoral proliferation was revealed, measuring about 5 mm and consisting of glands of various shapes and sizes, some of them dilated, with intraluminal papillary projections, without a fibrovascular core. The glands were lined by cuboidal or pseudostratified epithelium, with enlarged, elongated nuclei and prominent nucleoli. Immu- nohistochemically, the tumoral glands were positive for AMACR and nega- tive for p63, highlighting the absence of basal cells. The differential diagnosis was ductal adenocarcinoma and HG-PIN, but both were excluded by the morphology and the immunohistochemical stains. A diagnosis of PIN-like adenocarcinoma was established, Gleason score 3+3=6, grade group 1. Conclusion: PIN-like carcinoma of the prostate is a relatively new entity, being reclassified as a subtype of acinar prostate carcinoma rather than ductal adenocarcinoma in the 5th edition of the WHO Blue Book. This lesion represents a challenge for pathologists, being particu- larly important to avoid under or over-diagnosis for optimal treatment and outcome of the patient. In our case, the tumour was identified incidentally, emphasizing once again that a low PSA level does not completely exclude the existence of cancer. E-PS-24-065 Post immunotherapy nephrectomy specimens - a series of three cases O.B. Popescu*, E.M. Fernandez, P. González Peramato *Hospital Universitario de Guadalajara, Spain Background & objectives: The incidence of kidney cancer has increased. The stage at diagnosis determines treatment options and influences survival. About 15% of cases have disseminated disease without surgical therapeutic option. Immunotherapy treatment is used for patients with advanced metastatic renal cancer. Methods: We report three cases of radical nephrectomy post neoadju- vant immunotherapy with surgeries performed between 2022 and 2023. All patients were male, mean age 63.3 years (55-67) diagnosed with clear renal cell carcinoma on biopsy. They had distant metastases in lungs, bones and soft tissues and underwent radical nephrectomy after a period of immunotherapy ranging from eight months to one year. Results: All radical nephrectomy specimens were received in formal- dehyde. Before sampling the margins, photographs were taken, and samples were weighed and measured. The mean tumour size was 8.16 cm (7.5-9). Two of the tumours were in the middle zone of the kidney and one in the upper pole. Macroscopically, whitish and firm areas were observed. The tumours were extensively sampled. On microscopic examination, areas of viable residual tumour cells were found rang- ing from 10% to 30%. Areas of regression showed accumulation of macrophages, fibrosis, inflammatory infiltrate and calcification. The pathologic stages were ypT1a, ypT2a and ypT3a with free margins. Conclusion: Gross examination and extensive sampling of these speci- mens is very important. Treatment with immunotherapy produces changes that can be identified macroscopically and histologically and can some- times be challenging. Adequate sampling provides an adequate result of the percentage of viable residual tumour and evaluation of complete/ partial response to treatment. To our knowledge, there are no guidelines on how to sample and report these specimens and as post neoadjuvant immunotherapy treatment is increasingly used there is a need for them. E-PS-24-066 An audit of the information provided to pathologists on bladder tumour location in transurethral resection of bladder tumour (TURBT) specimens S. Prendergast*, N. Mayer *Cork University Hospital, Ireland Background & objectives: We audited how often tumour location was included in the clinical details accompanying TURBT specimens. A tumour’s anatomical location may have staging implications for patients and facilitates tumour identification and sampling in subse- quent cystectomy specimens, particularly in the neoadjuvant context. Methods: TURBTs received in our department between January 1st 2021 and January 1st 2022 were searched for using appropriate SNOMED codes. Inclusion or omission of the tumour’s location in the clinical details was recorded in Microsoft Excel. The urology team were surveyed using an online questionnaire to assess if they routinely included this information and were aware of its value. Results: The standard to be met was that the clinical details should always provide this information. Of 168 TURBTs received, the majority (n=95, 57%) did not state the resected bladder tumour’s location on the request form, although this was routinely recorded in the clinical notes. Of these, 17 (18%) had muscle invasive cancer, prompting consideration of cystectomy. The urology team were consulted regarding our initiative to improve provision of this information. A sticker showing a schematic of the bladder was designed and made available in urology theatres. When affixed to specimen request forms, it allows the precise location(s) of a bladder tumour to be marked or drawn out by clinicians. Conclusion: The provision of details of tumour location with TURBT specimens was inadequate. To implement change, we designed and produced a sticker to be routinely affixed to specimen request forms to capture this information. This will direct block taking for any subse- quent cystectomy specimens, particularly in the neoadjuvant setting, leading to optimum diagnoses for patients and reduced block numbers and associated costs. The success of this initiative will be evaluated in a subsequent re-audit to close the audit cycle. E-PS-24-067 Thyroid-like follicular carcinoma of the kidney, a rare histologic subtype of renal cell carcinoma: a case report A. Raicea*, A. Loghin, C. Chibelean, T. Csilip, A. Borda *Pathology Department of Mures County Clinical Hospital, Romania Background & objectives: Thyroid-like follicular carcinoma of the kidney is a very rare subtype of renal cell carcinoma with histological features similar to those of well-differentiated thyroid follicular neo- plasms and is associated with a low malignant potential. Methods: We report the case of a 57 years-old woman admitted to the hospital during her regular clinical follow-up. An incidentaloma of