軟部腫傷を疑わせた巨大なRA肩峰下滑液包炎の一例

抄録

The present case of subacromial brusitis of rheumatoid arthritis (RA) was very difficult to make a diagnosis. It was commonly mistaken for a tumor, because it looked like a large soft tissue tumor, there was no local inflammation, it's content couldn't be aspirated and plain radiograms showed no specific signs.
(Cas e Report) A 41-year old man who was suffering from RA for 10 years had a large mass on his shoulder. The mass had no inflammatory sign. It's margin was not well defined. There was no adhesion to the skin. Active and passive shoulder joint motion was not limited. Plain radiograms showed a shadow of a soft tissue mass. Computed tomogram showed a homogeneous mass. So it was suspected of a soft tissue tumor. But surgical exploration of the shoulder revealed a very large subacromial bursa which was filled with jelly like substance of 450 grams. Histologic examination of the bursal membrane showed changes of chronic inflammation. Because the clinical and histological features showed it to be rheumatoid bursitis except that there was no villous formation in microscopic sections, we made a diagnosis of subacromial bursitis of RA.
In this manner, when you appraise a patient with RA who has larg e shoulder swelling, you had better remind not only a soft tissue tumor but subacromial bursitis also.