Sarcomas

 

Clinical Background

Sarcomas are a group of uncommon malignant tumors that arise in bone and soft tissue and have a wide range of histologic types and prognoses.

Epidemiology

  • Incidence
    • 2-4/100,000
    • <1% of all malignancies
  • Age – mean is 50s
    • 15% in children <15 years
    • 40% in adults >55 years
  • Sex –  M>F, 1.5:1, in Ewing and osteosarcoma

Classification

  • Most common subtypes (>50 subtypes)
    • Pleomorphic sarcoma (malignant fibrous histiocytoma)
    • Leiomyosarcoma
    • Liposarcoma
    • Synovial sarcoma
    • Neurofibrosarcoma (malignant peripheral nerve sheath tumor)
    • Osteosarcoma
    • Chondrosarcoma
    • Rhabdomyosarcoma
    • Gastrointestinal stromal tumors
    • Ewing sarcoma
    • Epithelioid sarcoma
    • Kaposi sarcoma
    • Fibrosarcoma

Risk Factors

  • Genetic
    • P53 – Li Fraumeni
    • NFI – neurofibromatosis type 1
    • RB1 – inherited retinoblastomas
    • KIT – familial gastrointestinal stromal tumor (GIST)
    • Beckwith-Wiedemann syndrome
  • Previous scar tissue
  • Previous radiation treatment – increases incidence 8- to 50-fold
  • Viruses
    • HIV (Kaposi sarcoma)
    • HHV8 (Kaposi sarcoma)
    • EBV (leiomyosarcomas in immunocompromised patients)
  • Paget disease of the bone (osteosarcoma)
  • Chronic lymphedema (Stewart-Treves syndrome) – lymphangiosarcoma

Pathophysiology

  • Mesodermal derivation from musculoskeletal tissues such as connective tissue, lymphatic vessels, smooth and skeletal muscle, fat, fascia and synovial structures

Clinical Presentation

  • 60% arise in the extremities
    • 3:1 ratio legs to arms
  • Soft tissue tumors
    • Asymptomatic mass is most common presentation
    • May have mechanical symptoms (eg, pain) due to entrapment, pressure or traction
  • Bony tumors
    • Pain and swelling of the affected area