Traumatic lesions of the axillary artery itself are limited to 2.9-9% of major arterial injuries. Pseudoaneurysms represent a pulsating encapsulated hematoma in communication with the lumen of a ruptured vessel. Traumatic pseudoaneurysm of the axillary artery is a rare sequela of injury to the shoulder region. We describe a case of posttraumatic pseudoaneurysm involving the axillary artery, which was initially misdiagnosed as an aggressive soft tissue tumor. The man presented 10 years after an injury from a fall from a tree with a slowly growing mass in the right upper limb region and reduced range of movement. This is a neglected case with a history of traditional massage. The patient presented a pathologic fracture of the right proximal humerus and dislocation of the glenohumeral joint. At the beginning, it was suggested to be a primary soft tissue tumor, but after several examinations, including comparable X-ray, ultrasound, and histopathology, the results did not support a soft tissue tumor. Magnetic resonance imaging and computed tomography angiography (CTA) finally confirmed the finding of a pseudoaneurysm of the right axillary artery associated with a huge hematoma with different age of the bleeding product and granulation tissue. This case demonstrates the necessity of early diagnosis of axillary artery pseudoaneurysm to prevent complications after a history of trauma. CTA is a useful modality to evaluate vascular injury and provides valuable information.