Fibro-adipose vascular anomaly:pathological characteristics of six cases

LV Wenfei; ZHANG Jing; YANG Xiangshan; YU Jing; HUANG Meng; ZHEN Junhui

doi:10.3969/j.issn.1007-8096.2025.07.010

Abstract：Objective To investigate the clinical features,histopathological features,diagnosis and prognosis of fibro-adipose vascular anomaly(FAVA).Methods The clinical data,histological characteristics,immunohistochemical phenotype and follow-up prognosis of 6 cases of FAVA collected from Shandong Provincial Third Hospital from 2020 to 2022 were reviewed and further analyzed in combination with domestic and foreign literature.Results Among the 6 cases of FAVA,5 cases were female and 1 case was male.The age of onset were 4,5,10,12,16,and 50 years old,respectively.Site of onset:2 cases were in the right lower limb,2 cases were in the left lower limb,1 case was in the left forearm,and 1 case was in the right posterior femoral intermuscular region.The clinical manifestations were slowly growing subcutaneous masses,soft and spongy,with unclear boundaries,limited joint movement and pain.The magnetic resonance imaging showed multiple irregular,stripy and clumpy abnormal signal shadows in the affected area.T1WI showed equal low signal shadows,and T2WI and lipid-pressure sequences showed uneven high signal.Under the microscope,lesions were all located in the deep subcutaneous area,with irregular dilated blood vessels,adipocytes,fibrocytes,lymphocytes,and plasma cells aggregates observed within the muscle tissue.Immunohistochemical staining showed positive expression of ERG and CD31 in blood vessels,positive expression of SMA in skeletal muscle tissues,and positive expression of S100 in adipose tissues in the 6 cases.Up to now,among the 6 cases that have undergone complete resection surgery,1 case recurred at the same site half a year later and underwent another surgery for complete resection without recurrence so far,while the rest have not recurred.Conclusion FAVA is a rare benign tumor with no obvious clinical specificity.The magnetic resonance and pathological morphology of FAVA have certain characteristics.To improve the understanding of its histological and pathologic characteristics and magnetic resonance is helpful to reduce missed diagnosis and misdiagnosis.