1	NERRS MSK Session Panel of Unknown Cases November 13, 2009 Peter T. Evangelista, M.D. Director of Musculoskeletal Radiology Assistant Professor of Radiology Rhode Island Hospital/ Warren Alpert Medical School of Brown University Providence, RI
2	Case #1
3	40 y/o woman with 2 month history of calf pain
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7	4 months later after conservative therapy. No fever or chills
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11	Lesion Description Central sclerosis, oblong Large surrounding bone marrow edema-like, enhances Fine, regular enhancement of periosteal reaction Mild thickening of the cortex, no deformity Equivocal enhancement of the central component No change 4 months later
12	Differential Adamantinoma Osteofibrous dysplasia Campanacci Brodie's abscess Osteoid osteoma Stress fracture
13	Adamantinoma Extremely rare, low-grade malignant tumor of epithelial origin Typically manifests with large, painful lesion of tibia Usually in patients older than 10 years Locally aggressive lytic lesion Presence of soft-tissue extension Intramedullary involvement Periosteal reaction in absence of pathologic fracture
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15	Osteofibrous dysplasia Campanacci Usually diagnosed in children under 10 De novo cases reported in adults Oldest aged 39 years Painless, with localized, firm swelling of tibia Most lesions affect cortex of tibia Predominantly middle third of diaphysis Eccentric Cortex often expanded and thinned, with multiple radiolucencies mixed with intervening areas of sclerosis Anterior tibial bowing
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17	Brodie Abscess Chronic low-grade osteomyelitis Medullary lytic lesion with marginal sclerosis MRI shows “target” lesion with 4 layers Center with low T1, high T2, and enhances Inner ring iso to muscle, and high T1 Outer ring hypo on all images Peripheral halo hypo on T1
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20	Osteoid Osteoma Too much sclerosis on CT No discrete nidus on both CT and MRI CT is ultimate diagnostic tool Precise localization of nidus Nidus enhances after iv contrast Nidus shows variable degree of mineralization: amorphous, punctate, ringlike, or, uniformly dense Reactive sclerosis around the nidus varies from being extremely dense to manifesting no reaction at all
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24	Findings
25	Differential diagnoses
26	Diagnosis
27	Case #2
28	10 y/o girl with 6 month history of left clavicular swelling and occasional pain, recently increasing. Afebrile.
29	10 yo, 6 months symptom Radiographic findings: Location: proximal and mid clavicle Sclerotic , expansile lesion Periosteal reaction: diffuse , thick, non-aggressive
30	Periosteal reaction: thick, non-aggressive
31	Soft tissues: edema & enhancement Mass: none
32	Osteosclerosis, periostitis and bone enlargement of the clavicle
33	Osteosclerosis, periostitis and bone enlargement of the clavicle
34	Trauma
35	Osteosclerosis, periostitis and bone enlargement of the clavicle
36	Osteosclerosis, periostitis and bone enlargement of the clavicle
37	Eosinophilic Granuloma
38	Osteosclerosis, periostitis and bone enlargement of the clavicle
39	Osteosclerosis, periostitis and bone enlargement of the clavicle
40	Chronic Recurrent Multi-focal Osteomyelitis (CRMO)
41	sapho
42	Sternoclavicular hyperostosis
43	Condensing osteitis of the clavicle
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45	CRMO
46	Crmo
47	Findings
48	Differential diagnoses
49	Diagnosis
50	"Radiographic appearance"
51	Case #3
52	54 y/o man with worsening chronic knee pain
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58	Findings Well defined punched out erosions Large joint effusion/synovitis Relative preservation of joint space given degree of involvement Intermediate to low signal synovial lesions
59	Differential diagnoses
60	Diagnosis
61	Case #4
62	43 y/o man with left knee pain and clicking
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65	Findings Lobulated mass with intermediate to slight T2 hyperintensity Intra-articular location Relatively homogeneous with some low signal septations
66	Differential diagnoses
67	Diagnosis
68	"Biphasic represents 20-30" Biphasic represents 20-30% of all lesions Often multilobular Heterogenous Triple sign on long TR images Jones BC, Sundaram M, Kransdorf MJ. AJR 1993;161:827-830. Calcification identified in up to 30% Murphey MD, et al. Radiographics. 2006;26:1543-1565.
69	Case #5
70	59 y/o woman with worsening posterior neck mass and pain
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77	Inflammatory Synovial Chondromatosis Ca²⁺, Erosions, T2- hyper, Epidural Spread Pain and Mass, 3^rd-5^th decade RA and Synovial Cyst No erosions of odontoid and minimal intra-spinal component Gout Synovial Cyst (degenerative or inflammatory)
78	Malignant Synovial Sarcoma T2 Hyper, Ca²⁺, can have epidural extension and cystic components No marrow edema, osseous destruction Chondrosarcoma Lymphoma Chordoma No vertebral body involvement
79	Infectious TB Most commonly involves spine or CNS
80	Findings Lobular T2 hyperintense mass centered at the right C2-C3 facet. Central foci of intermediate to low signal. Foci of calcification on CT No significant OA of facet. Mild remodeling of right C3 lamina Peripheral enhancement US shows lobular mass with foci of calcification
81	Differential diagnoses
82	Diagnosis
83	"Usually involves large joints" Usually involves large joints Rare case reports of vertebral involvement Rarely invades into medullary cancellous bone Can cause pressure erosion of cortex Typical lobular mass with T2 hyperintensity which can become low as cartilage calcifies.
84	Case #6
85	27 y/o man with neck pain
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88	Chordoma In favor Lytic lesion Centered in the midline Against Thin peripheral enhancement Bright on STIR but uncharacteristically low signal on T2
89	Low T2 signal Plasmocytoma Lymphoma Giant Cell Tumor Osteoid matrix Osteoblastoma Chondroid matrix Enchondroma Chondrosarcoma Chondroblastoma
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91	Low T2 signal + micro-lobulated margin + thin peripheral rim enhancement Chondroid lesions Low grade chondroid lesion Low grade chondrosarcoma Enchondroma
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93	Findings Lytic C3 lesion Intermediate to Low T2 signal and Intermediate T1. Mild hyperintense STIR signal Thin faint peripheral enhancment
94	Differential diagnoses
95	Diagnosis