Classification of soft tissue tumours

Soft tissue tumours are classified using the WHO classification, based on the morphological appearances of the tumour and whether or not it is benign or malignant. There are more than 50 variants of soft tissue sarcoma. The classification includes:

  • adipocytic tumours (eg lipoma, liposarcoma)
  • fibroblastic/myofibroblastic tumours (eg elastofibroma, adult fibrosarcoma)
  • so-called fibrohistiocytic tumours (eg GCT of tendon sheath, pleomorphic MFH)
  • smooth muscle tumours (eg angioleiomyoma, leiomyosarcoma)
  • pericytic tumours (eg glomus tumour)
  • skeletal muscle tumours (eg rahbdomyoma, rhabdomyosarcoma)
  • vascular tumours (eg haemangioma, angiosarcoma)
  • chondro-osseous tumours (eg soft tissue chondroma, extraskeletal osteosarcoma)
  • tumours of uncertain differentiation (eg intramuscular myxoma, synovial sarcoma)

Multidisciplinary team working

The principle of multidisciplinary team working has been enshrined in NHS culture since the publication of the NHS Cancer Plan in 2000.  It is particularly important that sarcomas are managed by specialist multidisciplinary teams because many aspects of diagnosis require discussion between clinicians, radiologists and pathologists, and the multi-modality nature of treatment for many sarcomas means that coordination is needed in order to tailor treatment to the needs of the individual patient. Sarcoma specialist multidisciplinary teams should include specialists in:

  • orthopaedic, plastic, general and thoracic surgery
  • medical (and paediatric) oncology
  • clinical (radiation) oncology
  • pathology
  • radiology
  • nursing
  • rehabilitation

Classification of primary bone tumours

Primary bone tumours can be classified according to the tissue of differentiation, using the WHO system. Tumours are classified as:

  • cartilage tumours (eg osteochondroma, chondrosarcoma)
  • osteogenic tumours (eg osteoid osteoma, osteosarcoma)
  • fibrogenic tumours (eg desmoplastic fibroma, fibrosarcoma)
  • fibrohistiocytic tumours (eg benign fibrous histiocytoma, malignant fibrous histiocytoma)
  • Ewing sarcoma/Primitive Neuroectodermal tumour (PNET)
  • Haemopoetic tumours (eg plasma cell myeloma)
  • Giant cell tumour of bone
  • Notochordal tumours (eg chordoma)
  • Vascular tumours (eg haemangioma)
  • Smooth muscle tumours (eg leiomyosarcoma)
  • Lipogenic tumours (eg lipoma, liposarcoma)
  • Neural tumours (eg neurilemmoma)
  • Miscellaneous tumours (eg adamantinoma)
  • Miscellaneous lesions (eg aneurysmal bone cyst)
  • Joint lesions (eg synovial chondromatosis)
For more information look here.
A simpler classification can also be helpful:
  • Cartilage forming tumours
  • Bone forming tumours
  • Fibrous tumours
  • Non-matrix producing tumours

Seven questions to ask when looking at an x-ray

A good approach to looking at an X-ray demonstrating an abnormality in the bone is to ask seven questions:
  1. Where is the lesion?
  2. How large is the lesion?
  3. What is the lesion doing to the bone?
  4. What is the bone doing in response?
  5. Is the lesion making matrix?
  6. Is the cortex eroded?
  7. Is there a soft tissue mass?
(from Levesque et al. A Clinical Guide to Primary Bone Tumours)