{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T15:08:58Z","timestamp":1788793738880,"version":"build-2803163510"},"reference-count":14,"publisher":"SAGE Publications","issue":"7","license":[{"start":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T00:00:00Z","timestamp":1774310400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Int J Surg Pathol"],"published-print":{"date-parts":[[2026,10]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Collision tumors, composed of 2 histologically distinct neoplasms at the same site, are rare. They encompass a variety of subtypes, where either lesion may be benign or malignant and where they may \u201ccollide\u201d by direct invasion or metastasis. Carcinoma\u2013sarcoma collisions are especially uncommon, and so-called tumor-to-tumor metastasis is even rarer. Tumor-to-tumor metastasis involving lung adenocarcinoma has only been reported within benign mesenchymal tumors; no such report to date has described metastasis into a malignant soft tissue sarcoma.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Patient Presentation<\/jats:title>\n                    <jats:p>A 90-year-old man presented with a rapidly growing soft tissue mass on the anterolateral aspect of the right knee. Biopsy revealed high-grade leiomyosarcoma. Imaging also identified a dominant pulmonary nodule. The soft tissue mass was resected, revealing not only leiomyosarcoma but also a distinct glandular proliferation. Subsequent lung biopsy confirmed adenocarcinoma. Immunohistochemistry demonstrated that the glandular component within the sarcoma shared an identical profile with the lung tumor, consistent with metastatic lung adenocarcinoma into the primary sarcoma.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>This is the first reported example of lung adenocarcinoma metastasizing into a malignant soft-tissue tumor, representing a rare tumor-to-tumor metastasis resulting in a carcinoma\u2013sarcoma collision tumor. A review of the literature identified 12 comparable reports, none involving both a malignant donor and a malignant mesenchymal recipient. This report underscores the importance of distinguishing such lesions from carcinosarcoma using histology and immunophenotyping.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This unique example of carcinoma-to-sarcoma metastasis expands the differential diagnosis of biphasic soft-tissue tumors. Accurate classification is critical for guiding treatment, which may require tailored oncologic strategies addressing both tumor types.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/10668969261422689","type":"journal-article","created":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T08:20:02Z","timestamp":1774340402000},"page":"1813-1818","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Collision Tumor of Metastatic Lung Adenocarcinoma to Lower Limb Leiomyosarcoma: Case Report and Literature Review"],"prefix":"10.1177","volume":"34","author":[{"given":"Mark","family":"Strong","sequence":"first","affiliation":[{"name":"NYU Langone Health"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3875-3492","authenticated-orcid":false,"given":"Nicholas","family":"Frazzette","sequence":"additional","affiliation":[{"name":"NYU Langone Health"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fang","family":"Zhou","sequence":"additional","affiliation":[{"name":"NYU Langone Health"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicola","family":"Fabbri","sequence":"additional","affiliation":[{"name":"NYU Langone Health"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syed T.","family":"Hoda","sequence":"additional","affiliation":[{"name":"NYU Langone Health"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,3,24]]},"reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1111\/dth.14236"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1097\/00000372-199406000-00005"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1172\/jci.insight.155309"},{"issue":"11","key":"e_1_3_2_5_2","first-page":"15143","article-title":"A collision tumor of esophagus","volume":"8","author":"Yao B","year":"2015","unstructured":"Yao B, Guan S, Huang X, Su P, Song Q, Cheng Y. 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