Diagnostic Pitfalls: Soft Tissue Sarcomas Initially Misdiagnosed As Benign Vascular Anomalies – A Case-Report And Systematic Review

Malgorzata Styczewska¹Weronika Lyzinska²Stanislaw Maria Wardecki³Joanna Zajaczkowska²Michał Kunc⁴Boguslaw Mikaszewski⁵Rafal Maciag⁶Bartosz Regent⁷Dariusz Wyrzykowski⁸Anna Jankowska⁷Dominik Świętoń⁷Katarzyna Sinacka⁷Katarzyna Zak-Jasinska^1,9Anna Jedrzejczyk⁹Malgorzata Krawczyk¹Ewa Bien^1*

• ¹Department of Pediatrics, Hematology and Oncology, Medical University of Gdansk, Gdansk, Poland
• ²Physician’s Assistant, Department of Pediatrics, Hematology and Oncology, University Clinical Center in Gdansk, Gdansk, Poland
• ³The English Division Pediatric Oncology Scientific Circle, Medical University of Gdansk, Gdansk, Poland
• ⁴Department of Pathology, Medical University of Gdansk, Gdansk, Poland
• ⁵Department of Otolaryngology, Medical University of Gdansk, Gdansk, Poland
• ⁶2nd Department of Clinical Radiology, Medical University of Warsaw, Warsaw, Poland
• ⁷Department of Radiology, Medical University of Gdansk, Gdansk, Poland
• ⁸Department of Pediatric Surgery and Urology, Copernicus Hospital in Gdansk, Gdansk, Poland
• ⁹St. Lawrence Hospice Association, Gdynia, Poland

ABSTRACT Introduction Vascular anomalies (VAs), comprising vascular tumors and malformations, are commonly diagnosed based solely on clinical evaluation and imaging. Soft tissue sarcomas (STS) may mimic VAs clinically and radiologically, leading to misdiagnosis, delayed treatment, and suboptimal outcomes. This systematic review aimed to summarize patients with a pathological diagnosis of STS who were initially misdiagnosed with benign VAs, highlighting diagnostic pitfalls. Materials & Methods This systematic review (PROSPERO ID: CRD42024615285) followed PRISMA 2020 guidelines. Inclusion criteria were patients with histologically confirmed STS, initially misdiagnosed as benign VAs based on clinical and/or radiological features. Literature from five databases was reviewed without language or date restrictions. One additional case of alveolar soft part sarcoma initially misdiagnosed and mistreated as an arteriovenous malformation from the authors' institution was added to the analysis. Results The systematic search yielded a total of 96 patients with STS initially misdiagnosed as benign VAs (95 from 77 publications, one own case). Median age at presentation was 6 months (range: newborn–88 years). The most frequent symptom was a swelling or a mass (75%). In most cases, the misdiagnosis was both clinical and radiological. Median diagnostic delay was 5.5 months. Fifty-nine (61.5%) patients received treatment for the misdiagnosed benign VA, including local interventions (51.0%) and systemic therapies (17.7%). The most commonly misdiagnosed STS subtypes were infantile fibrosarcoma, alveolar soft part sarcoma, rhabdomyosarcoma, dermatofibrosarcoma protuberans, angiosarcoma, and Ewing sarcoma. Conclusions Several STS subtypes may mimic benign VAs clinically and radiologically. Misuse of outdated terminology and limited awareness among clinicians contribute to diagnostic delays. To avoid misdiagnoses, the care for patients with benign VAs should be provided by specialists familiar with the classification and natural history of these lesions. In patients diagnosed with benign VAs based on clinical and/or imaging features only, all findings should clearly support the diagnosis. Any ambiguity warrants prompt referral to a tertiary center. A biopsy should be considered in doubtful or atypical cases.