Abstract： Objective To further understand the clinical features and the causes of misdiagnosis of pancoast cancer.Methods The data of 26 cases of pancoast cancer from 1999-2006 were collected for a retrospective review. The clinical and imaging features, and the causes underlying misdiagnosis were analyzed.Results There were 24 males and 2 females(mean age 59 ±6, range 44-70 years).The earliest clinical features of pancoast cancer included painful shoulder and back in 25 cases, upper extremity pain,palsy and numbness in 18 cases.Early respiratory symptoms such as cough and sputum were recorded in 5 cases, Horner syndrome in 2 cases, and hoarseness in 1 case.Misdiagnosis was made in 19 of the 26 cases:13 as periarthritis humeroscapularis,3 as cervical osteoarthritis and another 3 as pulmonary tuberculosis.CT scanning showed soft tissue masses at the apical segments of the lungs in all the cases(26/26).Three cases were misdiagnosed as "pulmonary tuberculosis" according to the images of X-ray, and another 3 went unnoticed.Conclusions Painful shoulder and back were the most common symptoms of pancoast cancer.pancoast cancer was often diagnosed at an advanced stage, and misdiagnosis was common.Thorax CT was the most valuable method for the detection of Pancoast cancer.