Nomenclature of primary bone lesions

¨ Malignant bone tumours (sarcomas): primarily metastasise via haematogenous route, especially to lungs.

¨ Benign bone tumours: range from small and limited to large and destructive.

¨ There are also many lesions that can simulate bone tumours

· Common non-mesenchymal lesions that occur in bone:

® metastatic bone disease

® myeloma

® lymphoma

Staging

· Criticalfor:evaluation,selection and planning of treatment,prognosis.

· Enneking system for malignant lesions (system for benign lesions outlined later):

 Grade

® G₂: high grade, chance of metastasis > 25% (most malignant lesions)

® G₁: low grade, metastasis < 25% (less common)

® morphology: based on anaplasia, pleomorphism and nuclear hyperchromasia:

¨ grade 1: well differentiated

¨ grade 2: less well differentiated

¨ grades 3 & 4: poorly differentiated

Tumour site

® T₁: intracompartmental (within the bone compartment)

® T₂: extracompartmental (outside the bone)

Metastases

® X-ray and CT of chest and technetium bone scan

® M₀: absent

® M₁: present

Enneking Staging System

Stage Description

1 Low grade

11 High grade

111 With metastases

add A if (intracompartmental)or B (extracompartmental)

Evaluation

Clinical Presentation