Clinical Scenario
Pathological Lesion

Scenario

A 82-year-old male has presented to clinic with increasing right thigh / hip pain. He has no history of trauma and reports weight loss of 1 stone over the past 3 months.

Interview Questions

Please interpret the radiograph and tell me what you are concerned about in this patient?

An AP radiograph of the right proximal femur is presented in an 82-year-old male. There is a lytic lesion at the junction of the proximal to middle third of the femur with cortical involvement. There is a narrow zone of transition with no periosteal reaction visible. This lesion is suspicious for a pathological lesion and requires further work up.

Key Concerns

Atraumatic hip fracture = Needs investigation for pathological fracture
Manage as per BOAST: Management of Metastatic Bone Disease [1]

What questions would you ask in this patient’s history? How would you examine them?

History

Pathological lesion Questions
- Preceding bone pain
- Weight loss, fevers, night sweats
- Systems review:
  - Thyroid - Hoarseness? Neck lumps?
  - Breast - Lumps?
  - Lung - SOB? Haemoptysis? Cough
  - Prostate - ?difficulty urinating
  - Kidney - ?haematuria
Previous bisphosphonate usage
Past medical history / social history (smoker)

Examination

NV intact?
Thyroid / breast / prostate / kidney / lung examination
Inguinal lymphadenopathy
Spinal Tenderness

Note: These patient's need full oncological history and examination work up. Should examine for 5 common areas for primary bone tumours.

What investigations would you order?

Investigations

Bloods
- FBC, U&Es, CRP, LFTs, Clotting
- Bone profile
  - (Raised Alkaline Phosphatase / Hypercalcaemia may raise suspicion of malignancy)
- Thyroid Function Tests (TFTs)
- Prostate Specific Antigen (PSA) + Myeloma screen
Imaging
- Xrays
  - Lateral view Hip
  - AP Pelvis
  - Full length-femur
- Specialist imaging:
  - CT CAP
    - Should be performed within 24 hours (as per BOAST)
  - MRI
  - Bone Scan

If you were suspecting a primary bone tumour, what would you do? What about management if suspecting a secondary bone tumour?

Management depends on whether there is a primary or secondary tumour

Primary Tumour

Refer to regional sarcoma unit
Discuss at Multi-Disciplinary Team (MDT) meeting
Bone biopsy to be performed at regional centre - usually undertaken by operating surgeon due to risk of seeding tumour along the biopsy track

Secondary Tumour

Discuss at MDT
Is solitary bone metastasis then should be referred to teritary referral unit (as per BOAST)
Consider prophylactic fixation (e.g. IM Nailing) if impending fracture
Other treatment options include radiotherapy / chemotherapy

What patients should be referred to a tertiary referral unit?

As per BOAST guidance on Management of Metastatic Bone disease. The following should have referral onwards to a tertiary referral unit:

Primary bone tumours - within 72 hours
Solitary bone metastases

Metastatic disease without an obvious primary site should be discussed with acute oncology services

What are the most common primary sites for metastatic bone lesions? Which of these are classically lytic? Sclerotic? Mixed?

Metastatic Disease

Most Common Primary Sites

Thyroid
Breast
Lung
Kidney
Prostate

Appearance

Sclerotic (blastic) = Prostate
Mixed = Breast
Lytic = Thyroid / Renal / Lung

If a patient had a renal cell carcinoma metastasis, what might you consider prior to surgical fixation?

Renal Cell Carcinoma metastases are extremely vascular and pre-operative embolization should be considered to reduce risk of bleeding during fixation

What criteria can be used to predict need to perform prophylactic fixation in metastatic bone lesions?

Mirels’ Criteria [2]

Predicts risk of pathological fracture in patients with long bone metastases
Can be used to help decision whether to perform prophylactic fixation
Consists of four separate criteria with a score of 1-3
- (3 indicating higher risk of fracture)
- Addition of 4 criteria numbers gives overall risk
A score of greater than or equal to 8 = prophylactic fixation

What are the aims of surgery in metastatic bone cancer treatment?

Survive surgery
Allow Immediate full weight bearing
Implant should outlive patient
Protect entire length of bone
Pain relief

"BOAST guidelines recommend that surgery should be consultant-led, aim for long-term durability, and allow immediate weight-bearing.

If performing a prophylactic IM nail fixation on this patient - what should be done prior to nail insertion?

Venting of the IM canal when performing IM nailing – can reduce the risk of fat embolization

Describing a bone tumour on Radiographs

Location - Which bone? / Where abouts in the bone? (Diaphyseal Vs metaphyseal)
Size
Transition Zone - Narrow Vs wide
Periosteal Reaction
Cortical Involvement
Matrix Appearance - Osteoid Vs Chondroid

What is the definition of subtrochanteric fractures?

Definition: Typically defined as an area from the lesser trochanter to 5cm distal to the lesser trochanter

When presented with a subtrochanteric fracture need to exclude:

Pathological Fracture OR
Bisphosphonate Fracture

What are the features of bisphosphonate related fracture on radiographs?

Bisphosphonate Related Fractures

Around 80% of subtrochanteric fractures are associated with long-term bisphosphonate usage
These fractures are associated with increased healing times
Fractures fail in tension - starting at lateral aspect of femur - then spreads to medial aspect causing cortical beaking

What are the features of bisphosphonate related fracture on radiographs?

Classical Features on Radiograph (see images below)

Increased cortical thickening
Transverse / short oblique fracture orientation
Medial Spike = cortical beaking
Lack of comminution

References

[1] BOA. BOAST- Management of Metastatic Bone Disease. Available online at: https://www.boa.ac.uk/resource/boast-management-of-metastatic-bone-disease.html

[2] Mirels H. Metastatic disease in long bones: A proposed scoring system for diagnosing impending pathologic fractures. Clin Orthop Relat Res. 2003;415:S4-13