Medicine

Bone Tumors Introduction

An introduction to classifying and understanding bone tumors of the body.
 

Primary bone tumors are rare after the first decade but secondary bone tumors are relatively common after this time.

Clinical Features

Malignant (Primary or Metastasis) presents with local pain and swelling for weeks or months, that worsens on exertion ad at night. There may or may not be a soft tissue mass. Red flags to look out for are:

  • persistent skeletal pain
  • localized tenderness
  • spontaneous fracture
  • enlarging mass/soft tissue swelling

Benign tumors are usually asymptomatic. Bone tumors are usually found after minor trauma brings attention to lesion.

Characteristics of Bone tumors

Benign

  • No periosteal reaction
  • Thick endosteal reaction
Endosteum 1
Periosteum Two
  • Well developed bone formation
  • Intraosseous and even calcification

Malignant

  • Acute periosteal reaction
    • Codman’s triangle
    • Onion skinning
    • Sunburst appearance
  • Broad border between lesion and bone
  • Varied bone formation
  • Extraosseous and irregular calcification
Codmans Triangle

Codman triangle is the triangular area of new subperiosteal bone that is created when a lesion, often a tumour, raises the periosteum away from the bone. A Codman triangle is not actually a full triangle. Instead, it is often a pseudotriangle on radiographic findings, with ossification on the original bone and one additional side of the triangle, which forms a two sided triangle with one open side. This two sided appearance is generated due to a tumor (or growth) that is growing at a rate which is faster than the periosteum can grow or expand, so instead of dimpling, the periosteum tears away and provides ossification on the second edge of the triangle.

The main causes for this sign are osteosarcoma,** Ewing’s sarcoma, eumycetoma, and a subperiosteal abscess**.

Possible x-ray findings

  • Lytic, lucent sclerotic bone
  • Involvement of the cortex, medulla and/or soft tissue
  • Radiolucent, radio opaque or calcified matrix
  • Periosteal reaction
  • Permeative margins
  • Pathological fracture (may be presentation)
  • Soft tissue swelling

Diagnosis

Rapid growth suggests malignancy as well as warmth, tenderness (active inflammation reation), and lack of defined margins.
When staging, include:

  • Blood work including liver enzymes

Any condition that causes liver(+biliary) damage and bone growth will release alkaline phosphatase (ALP). Any condition that affects bone growth or causes increased activity of bone cells can affect ALP levels in the blood. An ALP test may be used, for example, to detect cancers that have spread to the bones or to help diagnose. It may also be used to monitor treatment of Pagets Disease. Order Gamma-Glutamyl Transferase (GGT) to tell if ALP is coming from liver or bone.

  • CT chest (metastasis)
  • bone scan
  • bone biopsy
    • perform in specialist center
    • will classify tumor into benign, benign aggressive or malignant
  • MRI of affected bone