Extra-articular Synovial Chondromatosis Eroding and Penetrating the Acromion  George El Rassi, M.D., Jihad Matta, M.D., Ayman Hijjawi, M.D., Ousama Abou Khair, M.D., Sara Fahs  Arthroscopy Techniques  Volume 4, Issue 5, Pages e443-e448 (October 2015) DOI: 10.1016/j.eats.2015.04.001 Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 1 A photograph of a 57-year-old female patient with extra-articular synovial chondromatosis of the left shoulder (arrows) showing the severely swollen left shoulder on presentation. The size difference between the swollen left shoulder and the right shoulder should be noted. Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 2 Preoperative anteroposterior radiograph of left shoulder showing normal glenohumeral joint. Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 3 Preoperative magnetic resonance imaging of left shoulder. (A) Proton density (PD)–weighted T1 coronal view, (B, C) PD-weighted T2 sagittal views, (D) coronal view with fat saturation, and (E, F) PD-weighted sagittal views with fat saturation showing multiple oval loose bodies floating in the subacromial bursal space with a severely swollen bursa and expanding effusion around the rotator cuff (arrows). No loose bodies could be seen within the glenohumeral joint (asterisks). Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 4 Preoperative computed tomography scan of left shoulder, coronal view, showing erosion of the inferior surface of the acromion (arrows) with invasion of the soft tissue inside the acromial lumen (asterisk). Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 5 Shoulder arthroscopy. (A) Normal glenohumeral joint space showing long head of biceps tendon (LHBT) and humeral head (H). (B) Subacromial space showing numerous loose bodies (LB). A forceps (F) was used to remove large loose bodies. (C) A complete synovectomy was performed with a motorized shaver (Fr). (D) Debridement of the acromial defect was performed with a probe (Pr). (AC, acromial cortex.) Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions

Fig 6 A photograph showing hundreds of cartilaginous free bodies of various sizes with a mean diameter of 9 mm after arthroscopic removal from the left subacromial region. Arthroscopy Techniques 2015 4, e443-e448DOI: (10.1016/j.eats.2015.04.001) Copyright © 2015 Arthroscopy Association of North America Terms and Conditions