Tumor biology and incidence

  • Also known as undifferentiated high-grade pleomorphic sarcoma (World Health Organization)
  • Rare malignant tumor of mesenchymal origin (approximately 1-5% of all malignant bone tumors)
  • Exhibits a heterogeneous histology of spindle cells in a characteristic storiform or "starry night" pattern
  • May be primary or secondary
    • Secondary lesions arise in bone with bone infarcts, irradiated bone, Paget’s disease, and osteomyelitis


  • Usually occurs in older patients, although there are two peaks in incidence: ages 20-30 years and ages 50-60 years
  • Lesions generally secondary to underlying bone abnormality in older age group


M:F = 3:2


  • Localized pain, swelling, and a possible mass, possibly of several months’ duration
  • Up to 25% present with pathologic fracture
  • Serum alkaline phosphatase may be slightly elevated

Physical findings

  • Mass over involved area may be present
  • Swelling (most common finding)

Plain films


Usually greater than 5 cm

  • 75% of lesions localized to ends of long bones
  • 50% located in the femur; remainder involve, roughly in descending order, tibia, humerus, ribs, and pelvis
  • Lesion extends into epiphysis or diaphysis; isolated diaphyseal involvement rare (<10%)
Tumor effect on bone
  • Destructive lytic lesions
  • Permeative, ill-defined border
Bone response to tumor
  • Low-grade lesions may have sclerotic, well-defined rim; favorable prognostic sign
  • Little bony response in higher-grade tumors

Calcification of matrix or periosteal reaction rarely seen


Cortical destruction and soft tissue extension are characteristic

Soft tissue mass

May be present

Bone scan and chest CT

Necessary for systemic staging

CT scan

Useful in assessing amount of bone destruction


  • Useful in delineating intra- and extra-osseous components of mass
  • Essential for local staging of tumor extent

Differential diagnosis

  • Osteolytic osteosarcoma
  • Ewing sarcoma (younger patients)
  • Fibrosarcoma
  • Metastatic disease with spindle features
  • Multiple myeloma
  • Lymphoma
  • Melanoma
  • Primary leiomyosarcoma
  • Synovial sarcoma of bone
  • Dedifferentiated chondrosarcoma
  • Giant cell tumor

Natural history

  • 5-year survival rates of 50 to 70% with chemotherapy and surgical management
  • Patients with secondary malignant fibrous histiocytoma lesions have a worse prognosis


  • Gross:  Lesions usually grey-white and firm; may be brownish discoloration secondary to hemorrhage
  • Microscopic: Malignant spindle cells and pleomorphic cells in a storiform (starry night) pattern
  • Admixed malignant giant cells, multinucleated giant cells, and histiocytic cells usually present
  • May be myxoid change

Diagnosis and treatment

  • Biopsy, in consultation with a musculoskeletal surgical oncologist
  • Mainstays of treatment: chemotherapy and surgical management
    • Chemotherapy: adriamycin, methotrexate, cisplatin, or ifosfamide
    • Limb sparing surgery usually appropriate; only patients with unresectable tumors require amputation
    • Longer disease-free survival in patients with good response to neoadjuvant chemotherapy: as high as 94% in good responders versus 61% in poor responders
  • Radiation rarely used; may have a role in treatment of patients with micrometastic disease or unresectable tumors
  • Lung and other bones most common sites of metastatic lesions
    • 5-year survival rate in these patients is 10% if treated with aggressive chemotherapy and surgical resection

Recommended reading

Bullough P. Orthopaedic Pathology, 4th Ed. London, UK: Mosby, 2004.

Sarcoma meta-analysis collaboration. Adjuvant of chemotherapy for localized resectable soft-tissue sarcoma of adults:meta-analysis of individual data. Lancet 1997;350:1647-54.

Wittig JC and Villalobos CE: Other Skeletal Sarcomas, in Schwartz HS. Orthopaedic Knowledge Update: Musculoskeletal Tumors 2. Rosemont, IL: American Academy of Orthopedic Surgeons, 2007, pp 197-198.