Rib Destruction

Christopher M. Walker, MD

DIFFERENTIAL DIAGNOSIS

Common

Metastases
Multiple Myeloma
Bronchogenic Carcinoma

Less Common

Osteomyelitis
Ewing Sarcoma

Rare but Important

Chondrosarcoma
Osteosarcoma
Askin Tumor
Empyema Necessitatis
Langerhans Cell Histiocytosis
Lymphoma
Other Sarcomas

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Age of patient
- ≤ 30 years old
  - Ewing sarcoma
  - Askin tumor
  - Langerhans cell histiocytosis
  - Osteosarcoma
- ≥ 40 years old
  - Metastatic disease
  - Multiple myeloma
  - Bronchogenic carcinoma
Differentiate from benign causes that may expand ribs but do not destroy cortex
- Fibrous dysplasia, enchondroma, brown tumor

Helpful Clues for Common Diagnoses

Metastases
- Most common cause of rib destruction in adults
- Ribs contain red marrow so highly vascular
- Polyostotic (multiple lesions)
- History of primary tumor
- Most common tumors to metastasize to rib are breast, lung, kidney, or thyroid carcinoma
- Most common solitary rib metastasis secondary to thyroid or renal cell carcinoma
Multiple Myeloma
- 2nd most common cause of rib destruction in adults
- Most common bone manifestation is generalized osteopenia
- Solitary expansile lytic lesion may indicate solitary plasmacytoma
- Biopsy required for definitive diagnosis
Bronchogenic Carcinoma
- Rib destruction secondary to Pancoast tumor or hematogenous metastases
- Pancoast tumor
  - Syndrome of ipsilateral arm pain, Horner syndrome, and ipsilateral hand muscle wasting
  - Superior sulcus tumor invades apical fat to involve brachial plexus and sympathetic ganglia
  - Rib destruction is best sign to definitively diagnose chest wall invasion
  - MR occasionally used to assess for neurovascular invasion

Helpful Clues for Less Common Diagnoses

Osteomyelitis
- May be difficult to distinguish from Ewing sarcoma or Askin tumor
- Aggressive lytic lesion with wide zone of transition
- ± soft tissue mass
- Usually occurs in association with empyema, pneumonia, or chest wall infection
- Chronic osteomyelitis
  - ± periosteal reaction
  - ± sclerosis of involved ribs
Ewing Sarcoma
- 5-15% arise in ribs
- Adolescents and young adults usually present with painful chest wall mass
- Small round blue cell tumor
- Radiographic patterns
  - 80% are lytic with bone destruction
  - 10% are mixed lytic/blastic lesions
  - 10% are sclerotic
  - 40% have expanded rib
  - Most have disproportionately large soft tissue mass compared to osseous involvement
  - Intrathoracic component ≥ extrathoracic component
  - Metastasizes most commonly to bone
- Epicenter on rib
- Heterogeneity of mass reflects tumor necrosis
- Bone scintigraphy demonstrates increased activity in affected rib and helps diagnose metastatic disease

Helpful Clues for Rare Diagnoses

Chondrosarcoma
- Patient 30-60 years old ± chest wall pain
- Occurs anteriorly or near costochondral junction
- Radiographs and CECT show
  - Large mass with bone destruction
  - ± soft tissue involvement
  - Chondroid matrix (rings and arcs calcification)
Osteosarcoma
- Patient 10-30 years old with painful mass
- Bone destruction secondary to heterogeneous soft tissue mass
- ± cloud-like osteoid matrix
- Lung is most common site of metastatic disease
  - Metastases may calcify
Askin Tumor
- Form of primitive neuroectodermal tumor (PNET)
- Arises in soft tissues of thorax
- Children and young adults present with chest wall pain
- Radiographs show
  - Heterogeneous mass ± rib destruction
  - Rib destruction less common than Ewing sarcoma
  - ± pleural effusion
  - Metastasizes to lung and bone
Empyema Necessitatis
- Empyema that subsequently invades through chest wall
- Most common related bony abnormality
  - Rib sclerosis or periosteal reaction secondary to chronic osteomyelitis
- Organisms can be remembered by BATMAN pneumonic as BATMAN breaks through barriers
  - Blastomyces
  - Actinomyces
  - Tuberculosis (75% of cases)
  - Mucor
  - Aspergillus
  - Nocardia
Langerhans Cell Histiocytosis
- Expansile lytic lesion
- No sclerotic rim
- Polyostotic
- ± soft tissue mass
Lymphoma
- Heterogeneous or homogeneous soft tissue mass
- ± mediastinal lymphadenopathy
- Extrathoracic disease is common
- 30% have lung involvement
- Peaks in 5th-8th decades of life
Other Sarcomas
- Rib destruction seen with
  - Rhabdomyosarcoma, malignant fibrous histiocytoma, and synovial sarcoma