MRI findings and pathological analysis of intramuscular fibro-adipose vascular anomaly / 中华放射学杂志

ABSTRACT

Objective:To investigate the MRI and pathological features of intramuscular fibro-adipose vascular anomaly (FAVA).Methods:The clinical and imaging data of 44 patients with intramuscular FAVA confirmed by pathology from December 2012 to March 2021 in Henan Province People′s Hospital were retrospectively analyzed. Twenty-five females and 19 males were included, with the age of (15±6), from 5 to 29 years old. The clinical and MRI features including the type, location, boundary, signal intensity, enhancement mode and degree, and the vascular flow voids in the lesion were summarized and compared with pathological results.Results:The thigh and calf muscles were involved in 1 patient simultaneously, and 1 site was involved in 43 patients, including 20 calf muscles, 15 thigh muscles, 5 forearm muscles, 1 upper arm muscle, 1 gluteal muscle, and 1 shoulder muscle. The gastrocnemius muscle of lower leg was most commonly involved (13/44), followed by soleus muscle (10/44) and quadriceps femoris muscle (9/44). All the lesions were solid on MRI, including 24 cases of focal mass type, 15 cases of diffuse infiltration type and 5 cases of local infiltration type. The long axis of all the lesions were consistent with the long axis of the muscles. All lesions showed inhomogeneously moderate hyperintensity on T 1WI and T 2WI, and significantly hyperintensity on fat suppression T 2WI. All lesions showed tortuous and dilated abnormal vessels, of which 18 cases showed vascular flow voids. Thrombosis was found in 10 cases. On contrast-enhanced imaging, the lesions showed moderate to obvious inhomogeneous enhancement. Pathologically, the diseased skeletal muscle was infiltrated by fibrous tissue, fat components, irregular abnormal veins and vessels, which led to inhomogeneous MRI signals. Among the 7 patients who underwent human PIK3CA gene mutation detection, and 6 were mutant. Conclusions:Intramuscular FAVA has certain characteristics in clinic, MRI imaging and histopathology, and its MRI signal characteristics can reflect its complex pathological components.