Lipogenic tumours

Question 1

What is a lipoma?

Answer 1

• A **common benign tumour of Mature fat **
• maybe subcutaneous, extramuscular or intramuscular
• M>F
• pts 40-60 yrs
• develops in sedentary individuals
• location
  
  • superficial/Subcutaneous common
  • upper back/thigh/buttocks/shoulder/arm
  • deep in thigh/shoulders/arms
  • 5-10% multiple lesions
• Prognosis
  
  • size plateaus after initial growth

Question 2

Describe the classification of lipomas?

Answer 2

• Spindle cell lipoma
  
  • Males, 45-65
• Pleomorphic lipoma
  
  • middle ages pts
• Angiolipoma
  
  • unique that Painful when palpated
  • small nodules in upper arm
• Intermuscular lipoma
  
  • symptomatic often require marginal resection
• Hiberonoma- see pic
  
  • tumour of brown fat
  • young pts 20-40

Question 3

What are the symptoms of a lipoma?

Answer 3

• Painless mass that been present for a long time
  
  • angiolipoma exception

O/E

• Palpable, mobile, painless lesion

Question 4

What is seen on imaging of a lipoma?

Answer 4

• Xray
  
  • radiolucent lesion in the soft tissues
  • mineralisation should raise concerns of synovial cell carcinoma
• CT
  
  • lesion akin to subcutaneous fat
• MRI
  
  • Homogenous signal intenisty matches adipose tissue on all images sequencing
  • high signal T1
  • low (dark) T2 and STIR
  • dx often made so biopsy often not required

Question 5

What is the tx of lipoma?

Answer 5

Non operative

• Observation only
  
  • painless & MRi confirms dx

Operative

• Marginal resection
  
  • symptomatic lesions
  • mass rapidly growing
  • spindle cell/pleomorphic lipomas tx w marginal resection

Question 6

What is the complication of lipomas?

Answer 6

• Local Reoccurance
• <5%

Question 7

What is a liposarcoma?

Answer 7

• A Heterogenous class of sarcomas with differentation towards adipose tissue
  
  • the lipoblast ( signal ring type cell) is hallmark
• 2nd most common form of soft tissue sarcoma in adults
• lipomas not predisposition to liposarcomas
• 50-80yrs
• M>F
• occur deep fascia
• Lower extremity> upper extremity
• common in retroperitoneum
• genetics
  
  • myxoid liposarcoma- translocation (12,16)

Question 8

What is the malignancy potential with liposarcomas?

Answer 8

• Correlates w grade/subtype
• low grade met rate <1%
• Intermediate ( myxoid) met rate 10-30%
• High grade met rate >50%

Question 9

What is the prognosis of liposarcomas?

Answer 9

• well differentiated exhibit <10 local recurrence rates and <1% chance of mets & almost complete survival
• w appropriate tx, intermediate & high grade liposarcomas show -20% risk of local recurrence but they exhibit 5 years survival between 25-50%

Question 10

Describe the types of liposarcomas?

Answer 10

• All from primitive mesenchymal cells
• Well differentiated
• Myxoid
  
  • most common 50% liposarcomas
• Round cell
• Pleomorphic
• Dedifferentiated

Question 11

What is see on imaging of liposarcomas?

Answer 11

• xrays
  
  • may show calciifcation/ossification in well differentiated liposarcomas
• MRI
  
  • well differentiated similar to lipomas- T1 Bright, dark T2
  • high grade - see pic
    
    • T1 Dark- due to <10% of fat in lesion
    • T2 Bright
• Ct Chest/abdo/pelvis- esp in myxoid liposarcomas as tendency to met to areas outside lungs- retroperitoneal

Question 12

What is the tx of liposarcomas?

Answer 12

• Operative
  
  • marginal resection without radiotherapy
    
    • well differentiatied liposarcomas
    • low risk of recurrence, met extremely rare
  • Wide surgical resection with adjuvant radiotherapy
    
    • for ​intermediate/high grade liposarcomas
    • radiation reduces local recurrence
    • chemo may benefit some pts
    • myxoid liposarcomas w >10% round cells have high likelyhood of mets