Angioleiomyoma: Summary of Its Clinical Characteristics and Ultrasound Features and How to Improve Diagnostic Accuracy

Abstract Background: Due to its rarity and the limited clinical and imaging experience, angioleiomyoma is prone to misdiagnosis. Accurate imaging diagnosis, however, is crucial for guiding surgical management. This study therefore aims to investigate the clinical characteristics and sonographic features of angioleiomyoma, analyze the causes of ultrasound misdiagnosis, and compare it with commonly confused tumors. Methods: This retrospective study included 17 patients with a pathological diagnosis of angioleiomyoma. Clinical characteristics and ultrasound features were reviewed. Then we counted the tumors most easily confused with angioleiomyoma on ultrasound images, analysed the causes of misdiagnosis and further studied the difference between angioleiomyoma and its most misdiagnosed tumors. Results: Clinical characteristics showed that angioleiomyomas often occurred in female (64.7%), had no skin color changed (94.1%), had no progressive enlargement (70.6%), located in extremity (88.3%), all were solitary, half were without pain (52.9%), and all had no numbness. Sonographic features revealed that angioleiomyomas had small diameter (64.7%), all located close to or contact with dermis, all parallel to skin, were oval (88.2%), were solid (82.4%), were well defined (88.2%), were hypoechoic (76.5%), had inhomogeneous echo(76.5%), had no calcification (94.1%), and had vascularity (70.6%). Angioleiomyoma is most likely to be misdiagnosed as peripheral nerve sheath tumors (PNSTs, including schwannoma and neurofibroma) on ultrasound. There were significant differences between PNSTs and angioleiomyoma in progressive enlargement ( P =0.008), diameter ( P =0.001), subcutaneous location ( P =0.001) and numbness ( P =0.038). Conclusion: Angioleiomyoma usually present as a painful solitary slow-growing nodule on an extremity, particularly the lower leg. In US, it may be close to the epidermis, oval, solid, hypoechoic, with well-defined margin, present vascularity and rare calcification. Compare to PNSTs, angioleiomyoma has rare history of progressive enlargement, smaller diameter, more superficial location and rare numbness.