Bone tumors differential diagnosis

When we are confronted with a plain film of a bone , we must think about 6 points to narrow the differential diagnosis of the case.

This six clues are as follow: 

1-The age of the patient:

 -focuses on the patient’s age. According to Edeiken, 80% of malignant tumors can be correctly diagnosed on the basis of age alone. For a solitary lucent bone lesion, the most likely diagnoses by age include:

-Under age 10: neuroblastoma (infants) and Ewing’s sarcoma of tubular bones

Age 10-30: osteosarcoma and Ewing’s sarcoma of flat bones

Age 30-40: reticulum cell sarcoma, fibrosarcoma, parosteal osteosarcoma, malignant giant cell tumor, and lymphoma

Over age 40: metastatic carcinoma, multiple myeloma, and chondrosarcoma.

 


 2-The second clue is the location of the lesion,if it is

- In the transverse plane:
a) Central - Enchondroma
b) Eccentric -GCT, osteosarcoma, chondromyxoid fibroma
c) Cortical - Non-ossifying fibroma, osteoid osteoma
d) Parosteal - Parosteal osteosarcoma, osteochondroma
-In the longitudinal plane:
a) Epiphyseal - GCT, chondroblastoma
b) Metaphyseal - Osteomyelitis, osteosarcoma
c) Diaphyseal - Round cell lesions, ABC, enchondroma.

 Then look to the lesion for pattern of bone destruction and matrix of the lesion.

3-The third clue is to define the pattern of the bone destruction you see,if it is

a-Geographical or

b-Moth eaten or

c-Permeative.

Examples:

a-geographical lesions such as non-ossifying fibroma and esinophilic granuloma.

b-Moth eaten appearance such as

1-myeloma.

2-metastases.

3-lymphoma.

4-ewings sarcoma.

c-Permeative lesion such as Round-cell lesions .

1-Myeloma.

2-Metastases.

3-Lymphoma.

4-Ewing's Sarcoma

5-Leukaemia

6- Neuroblastoma

7-Osteomyelitis.

 4-Clues by matrix of the lesion,which could be as follow:

a- Ossification (Osteoblastic process) - Well organized ossified mass with fluffy, cotton-like or cloud-like densities. eg. Osteosarcoma.

b-Calcification (Cartilaginous process)- Unorganized calcified matrix which is comma-shaped, punctate, annular or popcorn-like. Eg. Enchondroma, Chondrosarcoma, Chondromyxoid fibroma.

5-Clues By Density Of Lesion

- Sclerotic Cortical lesions- Osteoid osteoma- Brodie's abscess- Stress fracture-Lytic lesions in children- Eosinophilic granuloma 
- Neuroblastoma- Leukemia
-Lytic lesions in adult- Metastatic lesions (Lung, Kidney, Thyroid)- Multiple myeloma- Primary bone tumor
-Blastic lesion in children- Medulloblastoma- Lymphoma
-Blastic lesion in adult- Metastatic disease (Breast, Prostate)- Lymphoma- Paget's disease

6-The six clue is concerning with the type of periosteal reaction, is it unilamelated ( benign) ,multilamelated,perpendicular or with codemen triangle(malignant).

 7. Clues by number of lesion Multiple lesion: More often benign Malignancies with multiple lesions- Metastatic disease- Multiple myeloma- Lymphoma