We report the case of a 40-year-old man presenting at the emergency department with ankle and feet edema due to acute sarcoidosis (Lofgren syndrome). The diagnosis was suggested based on an ultrasound examination showing bilateral asymmetrical tenosynovitis of the flexor tendons with hypervascular subcutaneous cellulitis without any significant ankle and foot joint effusion or synovitis. This case report highlights the crucial role of ultrasound imaging as the first-line diagnostic tool in the investigation of a non-specific clinical condition, when performed by a knowledgeable sonographer with attention to detail. Radiologists performing ultrasound should be aware of the presenting ultrasound pattern of acute soft tissue sarcoidosis, and should include this entity in the differential diagnosis of patients with distal lower extremity swelling, tenosynovitis and hypervascular subcutaneous cellulitis, in order to narrow down the differential diagnosis and facilitate the clinical workup of the patient.