805 - Unusual Complication of First Rib Fracture: Degenerative Mass Mimicking Malignancy Causing Intercostal Neuralgia

Case Diagnosis: Degenerative Mass Secondary to First Rib Fracture

Case Description: A 55-year-old male with history of right first rib fracture 5 years prior, presented with right upper anterior chest and rib pain radiating to the right shoulder blade, right posterior arm, and right lateral elbow. The pain was reproduced upon palpation of the first rib in the area of previous fracture. The patient was initially diagnosed with thoracic outlet syndrome and referred to thoracic surgery. Chest CT revealed a mass located between the first and second ribs extending to the pleura but no venous or arterial compression. The mass was concerning for malignant post-traumatic transformation into osteosarcoma and the patient underwent tissue biopsy. The biopsy confirmed the mass to be non-malignant and degenerative tissue. The patient underwent diagnostic 1^st and 2nd intercostal nerve blocks, which provided 100% immediate pain relief. Subsequent pulsed radiofrequency ablation (RFA) targeting the first and second intercostal nerves resulted in a remarkable 75% reduction in pain.

Discussions: First rib fractures are typically caused by high-energy trauma and are known to heal well. However, in some cases, they can evolve into degenerative mass osteophytosis, which rarely may progress to osteosarcomas or osteochondromas. Mass effect from the 1^st rib fracture or subsequent degenerative osteophytosis has been reported to cause thoracic outlet syndrome (TOS) but intercostal neuralgia has not been reported, which makes this case unique.

Conclusions: First rib fractures typically present with symptoms of TOS, characterized by pain and neurological symptoms. In contrast, intercostal neuralgia is a less common finding. This case report is unique in that the presentation of a degenerative tissue mass between the first and second ribs, mimicking a malignant lesion, is an unusual complication of a first rib fracture. The significant reduction in pain following pulsed RFA highlights the effectiveness of this intervention in intercostal neuralgia.