Fig. 6

Different presentations of osteoarticular inflammatory involvement in a girl with pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) syndrome. a Coronal STIR of the anterior right knee demonstrates moderate effusion with synovial thickening (arrows) and surrounding soft tissue edema. b Axial STIR image at the mid-level of the metacarpals of the left hand demonstrates abnormal bone marrow signal of the fourth metacarpal bone with an associated loculated dorsal fluid collection that demonstrates a fluid-fluid level (arrow). c Sagittal T1-weighted image with fat suppression and intravenous contrast administration through the fourth metacarpal bone at the same presentation demonstrates ring enhancement of the dorsal fluid collection (black arrow). Moreover, there is extensive synovial thickening and enhancement of the fourth metacarpophalangeal joint (white arrows). d Sagittal T1-weigthed image of the right elbow with fat suppression and after intravenous gadolinium administration demonstrates moderate effusion with synovial thickening and enhancement (black arrow). There is a ring-enhancing fluid collection (abscess) extending from the joint into the soft tissue antero-medially (white arrow)