<span>This study reports the diagnosis and treatment of brachial plexus-associated intractable pain cause</span><span lang="EN-MY">d</span><span> by Pancoast syndrome, along with the associated literature review, based on a patient we attended to in April 2011. A full examination was performed after his admission, and neurolysis was conducted on the right brachial plexus of lower trunk. Follow-ups and treatment evaluations were carried out 1, 2, 3, and 6 months after the initial neurolysis procedure, which was followed by a radiation therapy two months later. The patient’s pain symptoms were relieved and he partially regained sense awareness and movement of his right hand. We found that early clinical manifestations of Pancoast syndrome are atypical and are sometimes difficult to detect. It is very similar to brachial plexus injury-related pain, and the patient must be referred to an orthopaedics or hand surgery specialist for treatment. Therefore, improving medical practitioners’ general understanding </span><span lang="EN-MY">of</span><span> this disease is essential in order to avoid potential misdiagnoses.</span>