{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T10:08:41Z","timestamp":1789380521586,"version":"build-2803163510"},"reference-count":42,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T00:00:00Z","timestamp":1789344000000},"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: Undifferentiated pleomorphic sarcoma (UPS) of the bone is a rare, high-grade malignancy of uncertain origin, most commonly affecting the extremities of adults. Its diagnosis may be challenging, particularly when clinical and radiological findings are confounded by trauma-related conditions. Case presentation: In this paper, the case of a 51-year-old man who sustained a high-energy trauma resulting in a diaphyseal fracture of the left tibia and fibula, initially treated with intramedullary nailing. Preoperative radiographs raised suspicion of an osteolytic lesion in the distal tibia; however, second-level imaging was performed postoperatively, suggesting a benign process. At initial evaluation at a primary Musculoskeletal Oncology Centre, strict clinical and radiological follow-up was recommended, but the patient failed to adhere. Over the following years, persistent symptoms were attributed to post-traumatic and inflammatory conditions, including suspected complex regional pain syndrome. Progressive clinical deterioration led to repeat imaging, revealing an aggressive lesion. A biopsy (March 2025) ultimately confirmed a primary bone high-grade UPS with no metastasis. Following multidisciplinary discussion, below-knee amputation was performed, achieving clear surgical margins. At one-year CT imaging follow-up, the patient remained disease-free and was able to ambulate with a prosthesis. Conclusions: High-energy trauma and later attribution of symptoms to post-traumatic conditions may complicate the diagnostic process, contributing to diagnostic delay. Early referral to specialised Musculoskeletal Oncology Centres, strict adherence to follow-up, and timely histological confirmation are essential to optimise outcomes. Suspicious bone lesions should always be fully characterised prior to surgical intervention.<\/jats:p>","DOI":"10.3390\/diagnostics16182971","type":"journal-article","created":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T09:34:01Z","timestamp":1789378441000},"page":"2971","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["High-Grade Undifferentiated Pleomorphic Sarcoma of the Distal Tibia Presenting as a Radiographically Benign-Appearing Lesion: A Case Report and Review of the Literature"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8517-0057","authenticated-orcid":false,"given":"Carlo","family":"Biz","sequence":"first","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Centre for Mechanics of Biological Materials, University of Padova, 35131 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elisa","family":"Pagliarini","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lorenzo","family":"Costa","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0889-1940","authenticated-orcid":false,"given":"Antonella","family":"Russo","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giuseppe","family":"Di Rubbo","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giulia","family":"Trovarelli","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9617-9882","authenticated-orcid":false,"given":"Pietro","family":"Ruggieri","sequence":"additional","affiliation":[{"name":"Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padova, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Department of Orthopedics and Orthopedic Oncology, Padua University\u2014Hospital, Via Giustiniani 3, 35128 Padova, Italy"},{"name":"Centre for Mechanics of Biological Materials, University of Padova, 35131 Padova, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"940.e1","DOI":"10.1016\/j.crad.2021.08.011","article-title":"Overview of malignant soft-tissue sarcomas of the limbs","volume":"76","author":"Renn","year":"2021","journal-title":"Clin. 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