Most common soft tissue sarcomas

#1 Undifferentiated pleomorphic sarcoma (historically known as malignant fibrous histiosarcoma)

#2 liposarcoma

MC in extremities 40%. Amputation is almost never the answer. Always limb sparing

This disease has a very high local recurrence rate

Sx: present with asymptomatic growing mass = MC presentation. GI bleed, bowel obstruction, neuro deficit

• High index of suspicion - large (>5 cm), fixation to underlying structures, immobility, variation in texture, deep location (subfascial, intra-abdominal, or intramuscular)

Syndromes associated with sarcoma: Li-Fraumeni, Gardner’s, NF-1

Hematogenous spread!!  Mets to nodes are rare

Biopsy: Will show spindle cells, arise from mesenchymal tissue

• Start with core needle biopsy

Lung MC site for mets

Staging is based on tumor HISTOLOGIC grade (undifferentiated is worse)

Most important to improve survival  R0 surgical resection

Tumor HISTOLOGIC grade is the most important prognostic factor.

Other prognostic factors: tumor size, pathologic stage

RF:

• Asbestos mesothelioma
• PVC, arsenic, vinyl chloride, thorotrast angiosarcoma
• Chronic lymphedema lymphangiosarcoma
• Previous radiation

Dx :

• Need the below imaging BEFORE any biopsy – need it to rule out vascular, nerve or bone invasion
  • All extremity/trunk/head/neck sarcomas need an MRI with IV contrast
  • All retroperitoneal lesions need abdominal CT
    • These also need core needle biopsy
• *After imaging CORE NEEDLE BIOPSY always first choice, if unable to get or fails then below:
  • Longitudinal incisional biopsy
    • Need to eventually resect biopsy skin site if + for sarcoma
  • Biopsy along the long axis plane of future incision for resection
  • Don’t raise flaps, or disturb tissue planes. Do not enucleate. Just do incisional biopsy leaving bulk behind
• !!!For visceral or retroperitoneal sarcoma – Imaging can be diagnostic, if it’s not then will need CNBx

Staging:

• Chest CT to rule out lung mets
• Extremity/Trunk Sarcoma
  • T1 - 5 cm or less
  • T2 - 5-10 cm → 1B or IIIA depending on G1 vs ≥G2
  • T3 - >10-15 cm → 1B or IIIB depending on G1 vs ≥G2
  • T4 - >15 cm → 1B or IIIB depending on G1 vs ≥G2
  • N0 - none
  • N1 - regional lymph node → Stage IV
• Grade definition - total differentiation, mitotic count, necrosis
  • G1 - 2 or 3 → IA or IB depending on T1 vs >T1
  • G2 - 4 or 5 → II, IIIA, IIIB depending on T
  • G3 - 6, 7, or 8 → II, IIIA, IIIB depending on T
  • Differentiation
    • 1 - sarcomas closely resembling normal adult mesenchymal tissue
    • 2 - sarcomas for which histologic typing is certain
    • 3 - Embryonal and undifferentiated sarcomas, sarcomas of doubtful type, synovial sarcomas, soft tissue osteosarcoma, Ewing sarcoma/primitive neuroectodermal tumor of soft tissue
  • Mitotic count
    • 1 - 0-9 mitoses per 10 HPF
    • 2 - 10-19 mitoses per 10 HPF
    • 3 - ≥20 mitoses per 10 HPF
  • Necrosis
    • 0 - none
    • 1 - <50%
    • 2 - ≥50%
• Prognostic stage groups
  • IA - T1, N0, M0, G1 or GX
  • IB - T2/T3/T4, N0, M0, G1/GX
  • II - T1, N0, M0, G2/G3
  • IIIA - T2, N0, M0, G2/G3
  • IIIB - T3/T4, N0, M0, G2/G3
  • IV - any T, N1 or M1, any G

Tx:

• Radical EN-BLOC resection with grossly negative, 1 cm margins and include the fascia. No frozen section.
  • Positive margins - resection with staged flap reconstruction
  • If you have positive margin go back to OR for resection, PLUS give radiation!!
• All cases need SNLB → if positive need additional images to evaluate lymph nodes
• Myxofibrosarcoma and dermatofibrosarcoma protuberans need 2 cm margins
• Need to include incision/core needle biopsy scars in resection
  • If nerves, vessels are near resection, they should be skeletonized
• < 5 cm, > 1 cm margin (1-2 cm is adequate), low grade → Do not need radiation
• Neoadjuvant radiation/chemo
  • >5 cm or high-grade Neoadjuvant radiation, especially if you want to downsize tumor
  • >5 cm or high-grade positive margins, recurrence if didn’t give neoadjuvant radiation, need adjuvant here
  • Neoadjuvant chemo for high grade tumors > 10 cm
• Local recurrence resect only if you can get R0 resection. 1-2 cm of free margin is adequate.
• Chemo and XRT have not changed survival, only decrease local recurrence
  • Metallic clips should be placed at surgical field periphery to guide future radiation
• Chemo has very limited role in sarcoma of extremities
• Always attempt limb salvage, try to avoid amputation
• Leave a drain after excision to avoid hematoma/seroma. Place close to surgical incision to be included in the radiation field
• Myocutaneous flaps and other complex closure should be planned in conjunction with tumor excision planning if primary closure is not feasible
• If sarcoma massively involves nerves, vessels, bone and would require amputation
  • Do neoadjuvant radiation
• Isolated mets should be resected!! Pulmonary metastectomy improves overall survival
• Only need wedge resection
• Midline incision for pelvic or retroperitoneal sarcomas
• Try to preserve motor nerves, and renal vessels

Poor prognosis for retroperitoneal sarcoma overall due to

Head and neck sarcoma

Retroperitoneal sarcoma

Kaposi’s Sarcoma

Childhood rhabdomyosarcoma