Discrepancy between the Radiographic Screening by Magnetic Resonance Imaging and Histopathologic Diagnosis of Vascular Malformations
Objectives Although magnetic resonance imaging (MRI) is widely used to evaluate extracranial vascular anomalies (VAs), its diagnostic accuracy remains uncertain. Methods We retrospectively assessed MRI accuracy for VAs and identified nonvascular lesions mimicking them. Patients who underwent surgical resection for suspected VAs at a tertiary referral center in Japan between April 2019 and June 2025 were analyzed. Results A total of 172 patients met the inclusion criteria (mean age 34.9 ± 18.8 years; 62.8% female). Lesions were most commonly located in the extremities (54.1%), followed by the head and neck (32.6%) and the trunk (13.4%). Histopathology identified venous malformations (VMs) as the most frequent subtype (73.8%), followed by arteriovenous malformations (AVMs; 11.0%) and lymphatic malformations (LMs; 6.4%). MRI showed moderate sensitivity and high specificity: AVM sensitivity 0.68 and specificity 0.99; VM sensitivity 0.70 and specificity 0.98; LM sensitivity 0.80 and specificity 0.98. Seven cases (4.1%) were ultimately diagnosed as non-VA lesions despite MRI findings suggestive of VAs. Common mimickers included angioleiomyoma and myopericytoma. Conclusions MRI demonstrates moderate sensitivity and strong specificity for VAs, although false-positive interpretations remain an important consideration.