Superolateral erosions of the humeral head in chronic inflammatory arthropathies.

Erosive lesions on the superolateral aspect of the humeral head were studied in 127 patients with chronic inflammatory arthropathies including rheumatoid arthritis (RA), juvenile rheumatoid arthritis (JRA), ankylosing spondylitis (AS), and psoriatic arthropathy (PA), as well as in a control group of 53 patients with non-inflammatory shoulder joint disease. Superolateral erosions were found in 39 out of 127 patients (31%), comprising 11/56 RA cases (20%), 22/50 JRA cases (44%), 4/9 cases of AS (44%), and 2/12 cases of PA (17%), but were absent in non-inflammatory disorders. Two morphologically distinct types of erosions were observed, an extensive one, present in all of the inflammatory conditions studied, and a circumscribed one occurring predominantly in JRA patients.