{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T18:15:31Z","timestamp":1787508931014,"version":"build-2736575974"},"reference-count":9,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,9,4]],"date-time":"2025-09-04T00:00:00Z","timestamp":1756944000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Joint Research Support Grants under the Comprehensive Agreement between Saitama University and Saitama Medical University","award":["22-J-01"],"award-info":[{"award-number":["22-J-01"]}]},{"name":"Joint Research Support Grants under the Comprehensive Agreement between Saitama University and Saitama Medical University","award":["23-J-08"],"award-info":[{"award-number":["23-J-08"]}]},{"name":"Joint Research Support Grants under the Comprehensive Agreement between Saitama University and Saitama Medical University","award":["24-J-02"],"award-info":[{"award-number":["24-J-02"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Epithelioid sarcoma (ES) is an extremely rare sarcoma categorized into classic and proximal types. Proximal ES is characterized by its occurrence in older individuals, proximal locations, deep tissue involvement, and a tendency to be larger in size. We present a case of an extremely small proximal ES occurring in the inguinal region, which posed significant diagnostic challenges. Clinically, the lesion presented as a painful mass, and magnetic resonance imaging findings suggested lymphadenitis or other inflammatory lesions due to its small size and internal signal patterns. Despite being monitored, the mass showed progression, prompting an incisional biopsy that raised suspicion for ES. Positron emission tomography\u2013computed tomography confirmed the absence of metastases, leading to wide excision. Pathological examination of the excised specimen confirmed proximal ES with negative margins. In this case, characteristic features of proximal ES were scarcely observed, and imaging findings were not distinctive, likely due to the small size of the lesion. Furthermore, the broad differential diagnoses for inguinal masses necessitate careful attention during diagnosis. For sarcomas and tumors in general, reliance solely on clinical and imaging findings can lead to diagnostic pitfalls, emphasizing the importance of active pathological evaluation through biopsy.<\/jats:p>","DOI":"10.3390\/diagnostics15172246","type":"journal-article","created":{"date-parts":[[2025,9,4]],"date-time":"2025-09-04T15:31:21Z","timestamp":1756999881000},"page":"2246","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Proximal Epithelioid Sarcoma Mimicking Inguinal Inflammation"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1629-2549","authenticated-orcid":false,"given":"Tomonori","family":"Kawasaki","sequence":"first","affiliation":[{"name":"Department of Pathology, Saitama Medical University International Medical Center, Hidaka, Saitama 350-1298, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-8109-6812","authenticated-orcid":false,"given":"Takuya","family":"Watanabe","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Oncology and Surgery, Saitama Medical University International Medical Center, Hidaka, Saitama 350-1298, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Satoshi","family":"Kanno","sequence":"additional","affiliation":[{"name":"Department of Pathology, Saitama Medical University International Medical Center, Hidaka, Saitama 350-1298, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomoaki","family":"Torigoe","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Oncology and Surgery, Saitama Medical University International Medical Center, Hidaka, Saitama 350-1298, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kojiro","family":"Onohara","sequence":"additional","affiliation":[{"name":"Department of Radiology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masanori","family":"Wako","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-5353-4477","authenticated-orcid":false,"given":"Tetsuhiro","family":"Hagino","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9850-6047","authenticated-orcid":false,"given":"Jiro","family":"Ichikawa","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,4]]},"reference":[{"key":"ref_1","unstructured":"Oda, Y., Dal Cin, P., Le Loarer, F., and Nielsen, T.O. (2020). Epithelioid Sarcoma. WHO Classification of Tumours, Soft Tissue and Bone Tumours, IARC Press. [5th ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Czarnecka, A.M., Sobczuk, P., Kostrzanowski, M., Spalek, M., Chojnacka, M., Szumera-Cieckiewicz, A., and Rutkowski, P. (2020). Epithelioid Sarcoma-From Genetics to Clinical Practice. Cancers, 12.","DOI":"10.3390\/cancers12082112"},{"key":"ref_3","first-page":"1","article-title":"An Index of Inguinal and Inguinofemoral Masses in Women: Critical Considerations for Diagnosis","volume":"12","author":"Gandhi","year":"2018","journal-title":"Transl. Res. Anat."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"973","DOI":"10.2214\/ajr.179.4.1790973","article-title":"Radiologic manifestations of proximal-type epithelioid sarcoma of the soft tissues","volume":"179","author":"Tateishi","year":"2002","journal-title":"AJR Am. J. Roentgenol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"922","DOI":"10.1007\/s00247-019-04389-2","article-title":"Magnetic resonance and computed tomography imaging features of epithelioid sarcoma in children and young adults with pathological and clinical correlation: A report from Children\u2019s Oncology Group study ARST0332","volume":"49","author":"McCarville","year":"2019","journal-title":"Pediatr. Radiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1007\/s00256-002-0509-9","article-title":"Epithelioid sarcoma: Clinical, MR imaging and pathologic findings","volume":"31","author":"Hanna","year":"2002","journal-title":"Skelet. Radiol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1243","DOI":"10.3892\/ol.2014.1876","article-title":"Role of FDG-PET\/CT for monitoring soft tissue tumors","volume":"7","author":"Hoshi","year":"2014","journal-title":"Oncol. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1097\/PAP.0000000000000102","article-title":"Epithelioid Sarcoma: Diagnostic Features and Genetics","volume":"23","author":"Thway","year":"2016","journal-title":"Adv. Anat. Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5729","DOI":"10.21873\/anticanres.16779","article-title":"Indolent Multinodular Synovial Sarcoma of Peripheral Nerves Mimicking Schwannoma: A Case Report and Literature Review","volume":"43","author":"Kawasaki","year":"2023","journal-title":"Anticancer Res."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/17\/2246\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:39:45Z","timestamp":1760035185000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/17\/2246"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,4]]},"references-count":9,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["diagnostics15172246"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics15172246","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,4]]}}}