Chronic non-compressible left thigh swelling with pain and muscle atrophy: A case of fibro-adipose vascular anomaly

Fibro-adipose vascular anomaly (FAVA) is a rare intramuscular vascular malformation characterized by fibro-fatty infiltration and abnormal venous channels, typically affecting young individuals. We report an unusual case of a 39-year-old female who presented with a 10-year history of progressive pain, swelling, and restricted movement of the left thigh. Ultrasound showed a heterogeneously echogenic lesion with serpiginous venous channels and calcific foci. The scanogram showed periosteal reaction along the femoral shaft with adjacent intramuscular calcifications. Non-contrast computed tomography demonstrated marked lipoatrophy of the quadriceps muscle with coarse calcifications and adjacent irregular periosteal reaction. Magnetic resonance imaging showed fibro-fatty muscle replacement, muscle atrophy, and serpiginous venous channels without flow voids involving the vastus medialis and intermedius. Based on multimodality imaging, a diagnosis of FAVA was suggested. This case highlights the importance of recognizing key imaging findings of FAVA to distinguish it from more common intramuscular lesions and guide appropriate management.