The MRI features and treatment of scapulothoracic bursitis: report of four cases.

Among cases of soft tissue tumours arising between the inferior angle of the scapula and thoracic wall, scapulothoracic bursitis has rarely been reported. All the reported cases were surgically treated and there have been no reports about the results of conservative treatment observed for a long period. Therefore, we retrospectively evaluated the clinical findings, magnetic resonance imaging (MRI) features, and treatment procedures in order to elucidate the differential diagnosis for, and efficacy of, conservative treatment. The patients were those who consulted our department of orthopedic surgery from 1994 to 1998 with complaints of thoracic back tumours. The patients were 2 men and 2 women whose ages ranged from 46 to 66 years. The tumour locations, MRI findings and treatments were evaluated. The cysts appeared in the inferior angle of the scapula with the shoulder flexed and adducted. There was neither pain nor tenderness, local heat nor redness. The cysts were elastic hard, fluctuating, and less mobile and the margins were well circumscribed by palpation. The diameters were from 6 x 6 cm to 20 x 15 cm. On MR imaging, the cysts were located between the serratus anterior muscle and the chest wall. Slightly high signal intensity on T1WI, high on T2WI and fluid-fluid levels were seen in the cysts in three cases. For the treatment, in one case we performed multiple aspirations until a reduction appeared to occur. The average aspirated contents of the cyst were 100 mL to 200 mL and were bloody-serous. In two cases no special treatments were employed, and in one case the tumour was surgically removed because it was unresponsive to aspiration. In the three cases with conservative treatment, the follow-up time was 8, 9 and 25 months, respectively. The tumours had disappeared in all cases at the time of the final follow-up. High signal intensities on T1 and T2 weighted images, and fluid-fluid level on T2 weighted images were very useful MRI features for the diagnosis of scapulothoracic bursitis. Our observations indicate that conservative treatment can be successful and surgery is not necessary except for cases with pain, excessive friction, or dysfunction.