QuestionSBA
QuestionChoice
This history is more concerning for malignancy given the development of a growing, painful bony lesion in an adolescent. Patients would be less likely to develop pseudogout at this age and X-ray would be more likely to show chondrocalcinosis (calcification of cartilage).
10017158
c
Pseudogout
QuestionChoice
This more commonly affects patients over the age of 40. Lytic lesions with ‘fluffy popcorn calcification’ are the characteristic X-ray findings.
10017157
b
Chondrosarcoma
QuestionChoice
This is the most common primary bone malignancy which typically affects adolescent males. A history of retinoblastoma is a risk factor for the development of osteosarcoma and the ‘sunburst appearance’ (formation of new bone in a specific pattern) is a classic finding on X-ray.
10017156
a
Osteosarcoma
QuestionChoice
Whilst trauma can present with pain and swelling, the developing size of the swelling means malignancy is more likely and needs to be excluded.
10017160
e
Trauma to the distal femur
QuestionChoice
This is a disease which causes inflammation of the growth plate and presents with pain and swelling of the tibial tuberosity rather than distal femur. This history and the X-ray findings are much more suggestive of malignancy.
10017159
d
Osgood-Schlatter disease
Concept
Chapter
# Summary

Osteosarcoma, Ewing's Sarcoma, and Chondrosarcoma are all examples of primary bone malignancies, which, while rare, are significant health concerns that are typically treated in specialist orthopaedic/oncology units. These cancers can present with common symptoms such as painful, warm swellings and systemic symptoms like fever and anaemia. Key investigations include X-rays, which may reveal specific patterns characteristic of these diseases, such as Codman's triangle in osteosarcoma or 'onion skin' periosteal reaction in Ewing's sarcoma. Management strategies vary, but often include surgical resection, radiation therapy, and systemic chemotherapy.

# Definition

Primary bone malignancies are rare cancers that originate in the bone, rather than spreading from other areas of the body (metastatic disease). They include various types, most notably osteosarcoma, Ewing's sarcoma, and chondrosarcoma.

# Epidemiology

Secondary tumours arising from metastatic disease are the most common type of malignancy encountered in bone. Primary bone tumours, including osteosarcoma, Ewing's sarcoma, and chondrosarcoma, are relatively rare and usually treated in specialist orthopaedic/oncology units.

# Aetiology

The exact causes of primary bone cancers are not entirely understood, although genetic factors, previous radiation exposure, and certain bone conditions such as Paget's disease may increase the risk.

# Signs and symptoms

-   **Osteosarcoma:** Typically presents with a warm, painful swelling, often around the knee.
-   **Ewing's Sarcoma:** Presents as a painful, warm, enlarging mass along long bone diaphysis. Systemic symptoms, such as fever and anaemia, may also be present, and blood tests may reveal a raised ESR and WCC.
-   **Chondrosarcoma:** Occurs in older patients (>40) and often presents with pain and a lump.

# Differential diagnosis

When presented with a patient experiencing bone pain and swelling, several conditions should be considered:

-   **Osteomyelitis:** Presents with bone pain, fever, and possibly swelling and erythema. Blood tests may show raised inflammatory markers.
-   **Benign bone tumours (e.g., osteoid osteoma, osteoblastoma):** Often present with localized pain that may be worse at night.
-   **Metastatic bone disease:** Can present with bone pain and fractures. May be associated with weight loss and a history of cancer elsewhere in the body.

# Investigations

The main diagnostic tool for primary bone cancers is an X-ray, which can reveal unique patterns:

-   **Osteosarcoma:** Periosteal reaction with Codman's triangle and a sunburst appearance. 

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-   **Ewing's Sarcoma:** 'Onion skin' periosteal reaction. 

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-   **Chondrosarcoma:** Lytic lesion with 'fluffy popcorn' calcification.

Further investigations can include blood tests, biopsy, MRI, CT scan, and bone scan.

# Management

Treatment for primary bone cancers often involves multidisciplinary teams and may include surgical resection, radiation therapy, and systemic chemotherapy. The specifics of treatment depend on the type, location, and stage of the cancer, as well as the patient's overall health.
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An x-ray showing Ewing's sarcoma.
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Osteosarcoma of the tibia.
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1051
Bone malignancies
Topic
37
Orthopaedics
15975
Osteosarcoma is the most common primary bone malignancy in adolescents, often presenting with a 'sunburst appearance' on X-ray.
A 14-year-old boy has a painful swelling just above his right knee, which is growing in size. A knee X-ray shows a ‘sunburst appearance’ of the distal right femur. He has a past medical history of retinoblastoma.

What is the most likely diagnosis?
a