case_images: PMC8129905_01
case_images: Imaging of the left shoulder before
  arthroplasty removal.
  (a) Axial CT image of the left shoulder demonstrating erosion of the anterior
  and central glenoid (solid yellow arrow) with heterogeneously
  hypoattenuating material centered within the glenohumeral joint space,
  suggestive of complex effusion (*) and multiple intra-articular fragments of
  ossific debris (arrowheads) abutting the margins of the thickened joint
  capsule. This appearance would be most suspicious for septic arthritis,
  though neoplasm with necrosis could have a similar appearance. Apparent
  linear and punctate calcification within the subacromial-subdeltoid bursa
  (dashed white arrows) would be most compatible with displaced articular
  debris and heterotopic soft tissue ossification, chondroid neoplasm not
  excluded. Streak artifact from the arthroplasty humeral component limits
  assessment of fine detail. (b) Anteroposterior radiograph of the left shoulder demonstrating erosive
  changes and extensive demineralization of the left proximal humerus (solid
  white arrow) with left shoulder arthroplasty hardware in place. Osseous
  fragmentation and erosion at the acromioclavicular joint, with secondary
  acromioclavicular joint separation (dashed white arrows), and ossific debris
  in the subacromial-subdeltoid bursa and/or soft tissue heterotopic
  ossification (arrowheads). There is additionally erosion and fragmentation
  of the glenoid (yellow arrow).
case_images: jbji-6-107-g01.jpg
case_images: PMC8129905_01_jbji-6-107-g01.jpg
case_images: Ch1.F1
case_images: The mass measured  cm and contained internal calcifications (Fig. 1a). A radiograph of the left shoulder demonstrated erosive changes and extensive demineralization of the left proximal humerus with left shoulder arthroplasty hardware in place (Fig. 1b), erosion and separation of the acromioclavicular joint, ossific debris in the subacromial-subdeltoid bursa, and destruction of the glenoid.
case_images: Imaging of the left shoulder 18 months after
  arthroplasty removal.
  (a) Anteroposterior radiograph of the left shoulder demonstrating erosion of
  the left proximal humerus at the site of explanted arthroplasty hardware
  (arrowheads) with extensive osseous mottling, demineralization, patchy
  sclerosis, and cortical thinning of the proximal humeral metadiaphysis
  (white arrows). Osseous fragmentation and erosion at the acromioclavicular
  joint, with secondary AC joint separation (dashed white arrow). These
  findings are highly suspicious for septic arthritis with osteomyelitis. (b) Coronal T1-weighted magnetic resonance image of the shoulder with fat
  saturation demonstrating peripheral gadolinium contrast enhancement
  (arrowheads) surrounding a moderate glenohumeral joint effusion in the
  location of the eroded humeral head (*) with extension to the
  subacromial-subdeltoid bursa (dashed arrow) and in continuity with a large,
  rim-enhancing proximal humeral metadiaphyseal intra-osseous abscess (white
  arrows).
case_images: jbji-6-107-g02.jpg
case_images: PMC8129905_01_jbji-6-107-g02.jpg
case_images: Ch1.F2
case_images: A radiograph of the left shoulder revealed erosion of the left proximal humerus at the site of explanted arthroplasty hardware, along with other findings highly suspicious for osteomyelitis and septic arthritis of the proximal humerus and acromioclavicular joint (Fig. 2a). Magnetic resonance imaging (MRI) demonstrated a peripherally enhancing glenohumeral joint effusion and intra-humeral abscess (Fig. 2b).