Synonyms

Central chondroma

Category

Bone

Behaviour

Benign

Gender

Both equally

Tissue of Origin

Cartilage

Epidemiology

• Common intraosseous cartilaginous tumour
• Peak incidence 2nd–4th decades
• Equal sex distribution
• Multiple enchondromas: Ollier disease (non-hereditary), Maffucci Syndrome (with haemangiomas)

Clinical Features

• Usually asymptomatic - incidental finding
• Pain suggests pathological fracture or Malignant transformation
• Pathological fracture in small Bones of hand/foot
• Ollier disease: limb length discrepancy, deformity

Location

• Small tubular Bones of hands and feet most common
• Femur, humerus (long Bones)
• Rarely in flat Bones

Imaging

• Geographic lytic lesion with ring-and-arc calcification
• No cortical destruction or periosteal reaction
• Endosteal scalloping <2/3 cortex thickness (>2/3 raises concern for chondrosarcoma)
• MRI: lobulated High T2 signal cartilaginous lesion

Pathology

• Lobules of hyaline Cartilage within medullary canal
• Bland cytology with minimal cellularity
• No significant nuclear atypia or binucleation
• IDH1/2 mutations in 50% of long Bone enchondromas

Genetics

• IDH1 (R132C/H) or IDH2 mutations in 50%
• PTH1R mutations in enchondromas of small Bones
• Ollier disease and Maffucci: somatic IDH1/2 mutations

Treatment

• Asymptomatic long Bone enchondromas: observation
• Hand enchondromas with fracture: curettage and Bone grafting after fracture healing
• Annual imaging surveillance for large lesions or in Ollier/Maffucci disease

Prognosis

• Excellent for solitary enchondroma
• Risk of Malignant transformation: <1% solitary; 25–30% in Ollier; 100% in Maffucci
• Regular imaging surveillance essential in Ollier/Maffucci

Key Points

• Distinguishing enchondroma from Low-grade chondrosarcoma is one of the most challenging problems in musculoskeletal pathology
• Pain without fracture and endosteal scalloping >2/3 are red flags for chondrosarcoma
• IDH mutation does not distinguish enchondroma from chondrosarcoma
• Maffucci Syndrome has near 100% lifetime risk of chondrosarcoma

Workup - Blood Tests

• No routine blood tests required for asymptomatic enchondroma
• FBC, U&E, LFTs - pre-operative baseline if surgery planned
• Bone profile - if multiple enchondromas (Ollier/Maffucci)

Workup - Local Imaging

• Plain radiograph
• MRI based on BACTIP protocol
• CT - better characterises calcification and cortical integrity; endosteal scalloping assessment

Workup - Biopsy

• Biopsy generally NOT required for asymptomatic typical enchondroma
• Core needle biopsy - if Malignant transformation to chondrosarcoma suspected (pain, growth, soft tissue mass)
• Histology: hypocellular hyaline Cartilage lobules, bland chondrocytes
• IDH1/2 mutation (R132C most common in enchondroma) - supports Benign diagnosis

Workup - Staging

• No staging required for solitary enchondroma
• Multiple enchondromas: screen for Ollier disease / Maffucci Syndrome (Vascular malformations)

Workup - Other

• Annual clinical and radiological surveillance for Ollier/Maffucci disease - High Malignant transformation risk (25%)
• Symptomatic enchondromas warrant MDT review to exclude grade 1 chondrosarcoma

Follow-up Summary

• Non-operative based on BACTIP protocol
• Year 1: Post-operative visit within first 6 weeks; 3–6 monthly clinical examination and plain films of primary site
• Years 2–3: 6-monthly clinical examination and plain films of primary site
• Discharge 3 years after surgery
• Craniofacial/sphenoid lesions: ophthalmological and neurological review at each visit