{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T15:48:30Z","timestamp":1778600910182,"version":"3.51.4"},"reference-count":20,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2015,3,21]],"date-time":"2015-03-21T00:00:00Z","timestamp":1426896000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["APMIS"],"published-print":{"date-parts":[[2015,4]]},"abstract":"<jats:p>Epithelioid sarcoma (<jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content>) is a rare malignant soft tissue tumor occurring in the distal extremities of young adults and is characterized histologically by nodules of epithelioid cells showing central necrosis. Intra\u2010articular <jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content> is extremely rare; only four cases have been reported, but their radiologic and histologic documentation of intra\u2010articular origin have been imprecise. We report the first radiologically and histologically well\u2010documented case of primary synovial <jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content>. A 59\u2010year\u2010old woman presented with pain followed by swelling of her right knee for 6\u00a0months. <jats:styled-content style=\"fixed-case\">MRI<\/jats:styled-content> revealed an entirely intra\u2010articular nodular synovial mass in the lateral part of the right knee joint in a background of diffusely thickened synovium. Synovectomy was performed under the clinical impression of pigmented villonodular synovitis (<jats:styled-content style=\"fixed-case\">PVNS<\/jats:styled-content>), a diagnosis erroneously confirmed by the reporting pathologist. The tumor rapidly recurred 3\u00a0months afterward and the diagnosis of primary synovial <jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content> was made. Despite above\u2010knee amputation, the tumor continued to spread proximally to the retroperitoneum. She developed multiple lung metastases and died 20\u00a0months after initial presentation. The nodular aggregates of tumor cells with central necrosis resulted in diffuse polypoid synovial thickening mimicking tuberculous synovitis and <jats:styled-content style=\"fixed-case\">PVNS<\/jats:styled-content>. The tumor cells showed positive staining for <jats:styled-content style=\"fixed-case\">EMA<\/jats:styled-content>,<jats:styled-content style=\"fixed-case\"> CK<\/jats:styled-content>19, <jats:styled-content style=\"fixed-case\">CD<\/jats:styled-content>34, and complete loss of <jats:styled-content style=\"fixed-case\">INI<\/jats:styled-content>1 staining, establishing the diagnosis of primary synovial <jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content>. The <jats:styled-content style=\"fixed-case\">ES<\/jats:styled-content> spread from the synovium to and along the joint capsule, and then extra\u2010articularly into the soft tissue surrounding the knee joint, with lymphovascular permeation. Such pattern of spread calls for radical surgical excision as the treatment of choice.<\/jats:p>","DOI":"10.1111\/apm.12352","type":"journal-article","created":{"date-parts":[[2015,3,21]],"date-time":"2015-03-21T08:20:56Z","timestamp":1426926056000},"page":"350-358","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Primary synovial epithelioid sarcoma of the knee: distinctly unusual location leading to its confusion with pigmented villonodular synovitis"],"prefix":"10.1111","volume":"123","author":[{"given":"Louis Tsun Cheung","family":"Chow","sequence":"first","affiliation":[{"name":"Department of Anatomical and Cellular Pathology Prince of Wales Hospital Hong Kong China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2015,3,21]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/1097-0142(197011)26:5<1029::AID-CNCR2820260510>3.0.CO;2-R"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-198504000-00001"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199702000-00002"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1097\/PAS.0b013e31819b92d5"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.reuma.2012.03.008"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF00204870"},{"key":"e_1_2_6_8_1","doi-asserted-by":"publisher","DOI":"10.1007\/s002560050417"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1097\/PAS.0b013e318215f732"},{"key":"e_1_2_6_10_1","first-page":"574","volume-title":"Orthopaedic Pathology","author":"Vigorita VJ","year":"2007"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00330-008-1024-8"},{"key":"e_1_2_6_12_1","doi-asserted-by":"publisher","DOI":"10.1007\/s003300000759"},{"key":"e_1_2_6_13_1","doi-asserted-by":"publisher","DOI":"10.1148\/rg.285085134"},{"key":"e_1_2_6_14_1","doi-asserted-by":"publisher","DOI":"10.1179\/acb.2010.008"},{"key":"e_1_2_6_15_1","doi-asserted-by":"publisher","DOI":"10.1097\/PAS.0b013e3181882c54"},{"key":"e_1_2_6_16_1","doi-asserted-by":"publisher","DOI":"10.1038\/modpathol.2010.71"},{"key":"e_1_2_6_17_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1440-1827.2006.01962.x"},{"key":"e_1_2_6_18_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF01606067"},{"key":"e_1_2_6_19_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11999-009-0749-2"},{"key":"e_1_2_6_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.prp.2014.08.008"},{"key":"e_1_2_6_21_1","doi-asserted-by":"publisher","DOI":"10.3928\/01477447-20140924-92"}],"container-title":["APMIS"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1111%2Fapm.12352","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/apm.12352","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,23]],"date-time":"2023-09-23T16:02:14Z","timestamp":1695484934000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/apm.12352"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,3,21]]},"references-count":20,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2015,4]]}},"alternative-id":["10.1111\/apm.12352"],"URL":"https:\/\/doi.org\/10.1111\/apm.12352","archive":["Portico"],"relation":{},"ISSN":["0903-4641","1600-0463"],"issn-type":[{"value":"0903-4641","type":"print"},{"value":"1600-0463","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,3,21]]},"assertion":[{"value":"2014-10-14","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2014-11-09","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2015-03-21","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}