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