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1
Ultrasound Evaluation of Masses
Jon A. Jacobson, M.D.
Professor of Radiology
Director, Division of Musculoskeletal Radiology
University of Michigan
Disclosures:
• Consultant: Bioclinica
• Advisory Panel: GE, Philips
• Book Royalties: Elsevier
Note: all images from the textbook Fundamentals of Musculoskeletal Ultrasound are copyrighted
by Elsevier Inc.
Question: tumor or pseudotumor?
• Pseudotumors:– Tendon tear with retraction:
• Rectus femoris, tibialis anterior
– Muscle hernia
– Anomalous muscle:
• Accessory soleus
• Extensor digitorum brevis manus
– Rheumatoid nodule
Rectus Femoris Tear: full tear, pseudomass
Long Axis
Muscle Hernia: anterior tibialis Accessory Soleus Muscle
Transverse
Achilles
2
Rheumatoid Nodules
Achilles
Question: anatomic location?
• Joint, tendon sheath, or bursal origin
– Synovial: benign
• Tendon– Gout
• Osseous origin
– Aggressive: infection or malignancy
• Soft tissue origin
– Variable etiology
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
Joint Recess
• Mass arising from a joint is a benign synovial process:
– Rheumatoid arthritis
– Pigmented villonodular synovitis
• Synovial sarcoma: very rarely involves a joint
Pigmented Villonodular Synovitis
Longitudinal Sagittal T1w post-Gado
Tibia
Talus
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
3
Bursa
• Mass arising from a bursa
– Benign synovial process
– Understand locations of normal bursa
– Anechoic or hypoechoic
– Compressible
– May be complex
– Example: Baker cyst
Baker Cyst
Transverse Longitudinal
SMMG MG
Bicipitoradial Bursitis
Long Axis to Biceps
Sagittal T2w
Bicipitoradial Bursitis
BT
Short Axis to Biceps
Axial T2w
Bicipitoradial Bursitis
Long Axis to Biceps: Lateral Approach
Gout: olecranon bursa
Olecranon
Humerus
4
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
Tendon
• Gout
– Popliteus tendon: knee
– Patellar tendon: inferior
– Other tendons
• Giant cell tumor of tendon sheath
• Pseudotumor:
– Tendon tear and retraction
– Rectus femoris, tibialis anterior
Gout: patellar tendon
P
T
Gout: popliteus
T2w
T2w
Tibia
Femur
Giant Cell Tumor of Tendon Sheath
Transverse Parasagittal
PhalanxPhalanx
Flexor TendonFlexor Tendon
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
5
Lymph Node
• Hyperplastic:
– Oval, hyperechoic hilum, hilar vascular pattern
• Malignant:
– Asymmetric thick cortex
– Round
– Loss of hyperechoic hilum
– Variable vascular pattern
Lymph Node: reactive
Longitudinal color Doppler
Lymph Node: reactiveB cell Lymphoma : axillary
AV
Lymphoma
Lymph Node: angiosarcoma metastasis
X X
X X
6
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
Ganglion Cysts
• Mass may correspond to a ganglion cyst
– Hypoechoic
– Multilocular
– Not compressible
– Specific locations
Ganglion Cysts
• Wrist:
– Dorsal: over scapholunate ligament
– Volar: between radial artery and FCR
• Knee:
– Cruciates, gastrocnemius tendon
– Hoffa’s fat pad
• Ankle:
– Tarsal tunnel
Ganglion Cyst: dorsal
RadiusLunate Capitate Lunate
Peroneal Intraneural Ganglion
• Joint fluid from proximal tibiofibular joint– Enters peroneal nerve via articular nerve
branches
– Shown at MR arthrography after exercise
– Extends proximal via epineurial sheath1
• May also form via tibial nerve2
1Spinner et al. Clin Anatomy 2007; 20:8262Spinner et al. Skeletal Radiol 2006; 35:172
Peroneal Intraneural Ganglia
From: Spinner et al. Skeletal Radiol 2008;37:1091
From: Spinner et al. Clin Anatomy 2007;20:826
7
Intraneural Ganglion
>15 cm
Atrophy Asymptomatic
Ganglion Cysts
• Differential diagnosis:
–Parameniscal cyst
–Paralabral cyst: hip and shoulder
Lateral Meniscus: tear and parameniscal cyst
Femur
Tibia
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
Subcutaneous Masses
• Lipoma
• Fat necrosis
• Epidermal inclusion cyst
• Other: benign versus malignant
Lipoma: subcutaneous
• Oval or oblong
• Homogeneous
• Isoechoic to adjacent fat
• Hyperechoic:– With increased fibrous
tissue components
• No internal vascularity
• Compressible
Inampudi et al. Radiology 2004; 233:763
8
Lipoma: subcutaneous Lipoma: subcutaneous
Lipoma: subcutaneous
Compression Sonopalpation
Lipoma: deep
• Variable echogenicity
• Often ill-defined
• Often difficult to assess
• Cannot reliably differentiate from low-grade liposarcoma!
• Need MRI
Paunipager et al. Insights Imaging 2010; 1:149
Lipoma: intramuscular
T1w
Liposarcoma: well-differentiated
• Hypoechoic
• Looks like a lipoma
• Need MRI with any suspected deep lipoma!
9
Fat Necrosis• Pain, palpable, focal
• Thigh, women
• No erythema
• Normal WBC
J Ultrasound Med 2008; 27:1751
T1w T2w+ FS Gado
Epidermal Inclusion Cyst:
• Trauma: implantation of epithelium
• Congenital
• Squamous metaplasia
• Hair follicle obstruction
Kim et al. Skeletal Radiol 2011; 40:1415
Epidermal Inclusion Cyst
Sagittal T1w
Coronal post-gado
Epidermal Inclusion Cyst: ruptured
Outline:
• Joint recess
• Bursa
• Tendon
• Lymph Node
• Ganglion
• Subcutaneous
• Other
Other Masses: malignant
• Sarcoma
• Metastasis
• Other
10
Synovial Sarcoma Tumor
Metastasis: Renal Cell Carcinoma
Sarcoma: high grade
Metastasis
Squamous cell carcinoma
Note: increased through-transmission (open arrows)
Melanoma
• Hypoechoic mass
• Usually increased flow on color Doppler
• Lymph node:– Focal cortical
enlargement
– Diffusely abnormal
Nazarian et al. AJR 1998; 170:459
Take Home Points
• Key to differential diagnosis:– Specific anatomic location
• Joint and tendon: benign
• Bursa: unilocular, compressible
• Ganglion: multilocular, not compressible
• Lipoma: subcutaneous, oval, compressible
• Malignancy: hypoechoic, heterogeneousSee www.jacobsonmskus.com for syllabus