{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T04:50:07Z","timestamp":1791521407137,"version":"4.3.4"},"reference-count":16,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T00:00:00Z","timestamp":1791158400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background: Mixed epithelial stromal tumour (MEST) is a rare biphasic neoplasm, most commonly arising in the kidney. Seminal vesicle involvement is exceedingly uncommon, and its clinical and imaging characteristics remain poorly defined. We present a rare case with detailed clinical and urological evaluation, multiparametric MRI characterisation, and radiologic-pathologic correlation. Case presentation: A 34-year-old man presented with recurrent acute urinary retention requiring repeated catheterization and, subsequently, an indwelling urinary catheter. Urological evaluation, including ultrasonography and cystoscopy, demonstrated marked mass effect on the bladder and prostatic urethra without an intravesical lesion. Contrast-enhanced CT and MRI revealed a large retrovesical mass arising from the right seminal vesicle, measuring approximately 11.5 \u00d7 9 \u00d7 10.5 cm. MRI demonstrated a predominantly multiloculated cystic lesion containing haemorrhagic or proteinaceous material, with an enhancing papillary solid component showing mild diffusion restriction and progressive enhancement. The lesion produced marked mass effect on the bladder, prostate, and rectum, without local invasion. Robotic-assisted resection of the right seminal vesicle was performed. Histopathology demonstrated a biphasic epithelial and stromal proliferation without atypia, necrosis, or increased mitotic activity, consistent with MEST. Conclusions: This case highlights the value of integrating clinical, urological, radiological, and pathological findings in the evaluation of a large complex retrovesical mass. Multiparametric MRI provided detailed characterisation of the solid-cystic architecture, with imaging features correlating with the epithelial and stromal components identified histologically. Recognition of this pattern may raise suspicion for MEST and help guide differential diagnosis and surgical planning, although definitive diagnosis requires histopathological and immunohistochemical evaluation.<\/jats:p>","DOI":"10.3390\/diagnostics16193222","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T14:43:18Z","timestamp":1791211398000},"page":"3222","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mixed Epithelial Stromal Tumour of the Seminal Vesicle Presenting with Recurrent Acute Urinary Retention: A Case Report"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8945-8979","authenticated-orcid":false,"given":"Daniel","family":"Vas","sequence":"first","affiliation":[{"name":"Department of Radiology, Hospital Clinic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-0974-1579","authenticated-orcid":false,"given":"Alessandra","family":"Iacono","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Imaging and Radiation Oncology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3505-8232","authenticated-orcid":false,"given":"Tarek","family":"Ajami","sequence":"additional","affiliation":[{"name":"Department of Urology, Hospital Cl\u00ednic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-1055-5888","authenticated-orcid":false,"given":"Silvia","family":"Valls","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hospital Cl\u00ednic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9841-4380","authenticated-orcid":false,"given":"Isabel","family":"Trias","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hospital Cl\u00ednic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3047-9804","authenticated-orcid":false,"given":"Daniel","family":"Corominas","sequence":"additional","affiliation":[{"name":"Department of Radiology, Hospital Clinic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2612-5250","authenticated-orcid":false,"given":"Antonio","family":"Alcaraz","sequence":"additional","affiliation":[{"name":"Department of Urology, Hospital Cl\u00ednic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1381-6442","authenticated-orcid":false,"given":"Carlos","family":"Nicolau","sequence":"additional","affiliation":[{"name":"Department of Radiology, Hospital Clinic de Barcelona, 08036 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,10,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1483","DOI":"10.5858\/133.9.1483","article-title":"Mixed epithelial and stromal tumors of the kidney: An overview","volume":"133","author":"Mohanty","year":"2009","journal-title":"Arch. Pathol. Lab. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1142","DOI":"10.1016\/j.urology.2007.11.106","article-title":"Adult cystic nephroma and mixed epithelial and stromal tumor of the kidney: Clinical, radiographic and pathologic characteristics","volume":"71","author":"Lane","year":"2008","journal-title":"Urology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"958","DOI":"10.1097\/00000478-200007000-00007","article-title":"Mixed Epithelial and Stromal Tumor of the Kidney","volume":"24","author":"Adsay","year":"2000","journal-title":"Am. J. Surg. Pathol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1097\/PAP.0000000000000057","article-title":"Mixed Epithelial-Stromal Tumor (MEST) of Seminal Vesicle: A Proposal for Unified Nomenclature","volume":"22","author":"Reikie","year":"2015","journal-title":"Adv. Anat. Pathol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1186\/1477-7819-6-101","article-title":"Low-grade mixed epithelial stromal tumour of the seminal vesicle","volume":"6","author":"Labanaris","year":"2008","journal-title":"World J. Surg. Oncol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"e239610","DOI":"10.1136\/bcr-2020-238526","article-title":"Laparoscopic resection of a large mixed epithelial-stromal tumour of the seminal vesicle","volume":"14","author":"Debnath","year":"2021","journal-title":"BMJ Case Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2050313X241277674","DOI":"10.1177\/2050313X241277674","article-title":"Mixed epithelial and stromal tumor of the seminal vesicle: A case report and literature review","volume":"12","author":"Wang","year":"2024","journal-title":"SAGE Open Med. Case Rep."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1186\/s13000-025-01647-w","article-title":"Mixed epithelial and stromal tumor of the seminal vesicles: Report of a rare case with diagnostic, therapeutic, and prognostic insights","volume":"20","author":"Saeed","year":"2025","journal-title":"Diagn. Pathol."},{"key":"ref_9","unstructured":"WHO Classification of Tumours Editorial Board (2022). Urinary and Male Genital Tumours, WHO. [5th ed.]."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"155797","DOI":"10.1016\/j.prp.2024.155797","article-title":"Incidental early mixed epithelial and stromal tumor of the efferent testicular-ductular system of the genitourinary tract: A small case series with literature review","volume":"268","author":"Daniels","year":"2025","journal-title":"Pathol. Res. Pract."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"384","DOI":"10.4103\/1008-682X.173440","article-title":"Rare primary seminal vesicle cystadenoma: Computed tomography and magnetic resonance imaging findings","volume":"19","author":"Wang","year":"2017","journal-title":"Asian J. Androl."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"840","DOI":"10.1016\/S0090-4295(97)00711-5","article-title":"Seminal vesicle cystadenoma: A case report and literature review","volume":"51","author":"Baschinsky","year":"1998","journal-title":"Urology"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"E259","DOI":"10.5489\/cuaj.127","article-title":"An unusual cause of hematospermia: Primary adenocarcinoma of the seminal vesicle","volume":"6","author":"Eken","year":"2012","journal-title":"Can. Urol. Assoc. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"143","DOI":"10.4103\/0970-1591.45557","article-title":"Primary adenocarcinoma of the seminal vesicle","volume":"25","author":"Ottlecz","year":"2009","journal-title":"Indian J. Urol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2055","DOI":"10.1002\/1097-0142(19930315)71:6<2055::AID-CNCR2820710621>3.0.CO;2-W","article-title":"Cystosarcoma phyllodes of the seminal vesicle","volume":"71","author":"Fain","year":"1993","journal-title":"Cancer"},{"key":"ref_16","first-page":"103538","article-title":"Seminal vesicle mixed epithelial-stromal tumor delayed local recurrence treated by salvage robotic Re-excision in a previously operated pelvis: A case report","volume":"68","author":"Tran","year":"2026","journal-title":"Urol. Case Rep."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/19\/3222\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T04:15:07Z","timestamp":1791519307000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/19\/3222"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,5]]},"references-count":16,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2026,10]]}},"alternative-id":["diagnostics16193222"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16193222","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,5]]}}}