Lymph Nodes

Question 1

Normal lymph node US appearance

Answer 1

• < 1cm AP diameter
• Shape: oval (long axis), C-shaped (short-axis)
• Hypoechoic cortex
• Hyperechoic fatty hilum
• Uniform vascular hilum

Question 2

Reactive lymph node

Answer 2

Normal response to local or systemic infection/ inflammation

Presents:

• Asymptomatic
• Swollen lump

Treatment:
- Treat underlying cause

Benign features:

• *Enlarged node**
• <1 cm AP diameter
• *Normal morphology**
• Oval, symmetrical cortex, fatty hilum, homogeneous, well defined,

Vascular hilum

Question 3

Lymphadenitis

Answer 3

Inflammed lymph nodes

Causes

• Bacterial infection (strep throat, tonsilitis, ear infection, salivary gland infection)
• Viral infection (common cold, upper respiratory tract infection)

Presents:

• Swollen tender cervical mass
• Erythema
• Fever
• Raised inflammatory markers

Management:

• Antibiotics
• US to assess for abscess formation
• *Enlarged nodes**
• Normal morphology

Increased vascularity

• *Matted mass**
• Fused nodes
• *Abscess formation**
• *-** Heterogeneous mass
• Thick irregular walls
• Increased peripheral vascularity

Question 4

Primary malignant lymph node (lymphoma)

Answer 4

Malignancy arising from lymphocytes
- Unknown cause

• Hodgkins (40%)
• Reed-Sternberg cells
• Metastasize → nearby nodes
• Better prognosis
• Non-Hodgkins (60%)
• No Reed-Sternberg cells
• Metastasize → random nodes
• B-cell: slower growing (more common)
• T-cell: aggressive

Present:

• Painless neck mass
• Fever
• Night sweats
• Weight loss

Treatment:

• Biopsy
• CT staging
• Surgical resection
• Chemo + radiation

Malignant features:

• *Multiple very hypoechoic nodes**
• *-** Absent hilum/ central necrosis
• Heterogeneous
• *Round**
• >1cm AP diameter
• Taller than wide

Lobulated/ irregular contour

Disorganised vascularity

Differential = mets (calcs)

Question 5

Metastatic lymph nodes

Answer 5

Metastases implant in subcapsular or cortical sinusoids → cortical thickening
- Location of implant determines pattern of thickening

Diagnosis:
- Biopsy

Asymmetric cortical thickening

Very hypoechoic

Round

Microcalcifications

Central necrosis (severe)

Differential = benign reactive node (symmetric cortical thickening)