Enchondroma

 

Shoulder EnchondromaHip enchondroma

 

Definition

 

Benign intramedullary cartilage lesion

 

Etiology

 

Enchondroma are presumed to be remnants of hyaline cartilage

Derived from the epiphyseal growth mechanism that failed to undergo enchondral ossification

 

Epidemiology

 

10% of benign bone tumours

Most frequent cartilaginous tumour

 

Young adults

 

Stop growing in adults and calcify

 

Malignant transformation 

 

Chondrosarcoma

- grade 1 / 2 / 3

- low / intermediate / high

 

Grade 1

- atypical cartilaginous tumour / low grade chondrosarcoma

- locally aggressive

- low metastatic potential

 

Can be difficult to diagnose on imaging including MRI

 

Location

 

Intramedullary

- long bones

- tubular bones of hand and feet

 

Clinical

 

Usually incidental finding

 

X-ray

 

Intralesional calcification - punctate, stippled calcification and broken rings

 

Differential diagnosis long bone with intralesional calcification

1.  Enchondroma

2.  Bone infarct 

3.  Chondrosarcoma

 

Enchondroma Distal Femur0001Enchondroma Distal Femur0002

 

Humerus enchondromaHumerus enchondroma 2

 

Hand / Foot

 

Enchondroma foot Thumb enchondroma

 

CT Scan

 

Shoulder EnchondromaShoulder Enchondroma CT

 

Enchon Sh 1Ench SH 2Ench Sh 3

 

MRI

 

MRI Enchondroma0001MRI Enchondroma0002

 

Enchondroma shoulder 1Enchondroma shoulder 2Enchondroma 3

 

Imaging differential diagnosis

 

Can be very difficult to distinguish between low grade chondrosarcoma / atypical cartilaginous tumour and enchondroma

 

Enchondroma versus chondrosarcoma

 

Murphey et al Radiographics 1998

- 92 enchondromas versus 95 chondrosarcomas

- factors associated with chondrosarcoma on presentation and imaging

- pain

- deep endosteal scalloping (>2/3 cortical thickness)

- cortical destruction

- soft tissue mass

- high uptake on bone scan

 

Crim et al Eur J Radiol 2015

- enchondroma versus grade 1 chondrosarcoma

- correct diagnosis enchondroma xray 67% and MRI 58%

- correct diagnosis chondrosarcoma xray 21% and MRI 58%

 

Low grade versus high grade chondrosarcoma

 

Douis et al Eur Radiol 2014

- 179 cartilaginous tumours

- MRI features associated with high grade versus low grade chondrosarcoma

- bone expansion / periostitis / soft tissue mass / tumour length

 

Chondrosarcoma

Endosteal scalloping

 

EnchondromaEnchondroma

Large, central enchondroma

 

Pathology

 

Composed of masses of hyaline cartilage without characteristic architecture

- typically bland cartilage

- no pleomorphism / anaplasia / hyperchromasia

 

Enchondroma Nephron GNU Free Documentation License Version 1.3

 

Histology differential diagnosis

 

Can be very difficult to distinguish between low grade chondrosarcoma / atypical cartilaginous tumour and enchondroma

- sampling issues

- difficult histological differentiation

 

Eefting et al Am J Surg Pathol 2009

- enchondroma versus grade 1 chondrosarcoma / atypical cartilage tumour

- low reliabilty (0.5 kappa)

- reliable signs mucoid matrix degeneration and host bone entrapment

 

Management

 

Typically surveillance of benign looking enchondroma

 

Surgical indications

 

Biopsy

- pain

- concerning radiological features

 

Risk pathological fracture

 

Curettage of low grade chondrosarcoma

 

Errani et al Eur J Orthop Surg Traumatol 2017

- 54 enchondroma and 35 patients atypical cartilaginous tumour (ACT) long bone

- treated with curettage

- no local recurrence with enchondroma

- 4/35 (11%) local recurrence with ACT

- 3/4 of those with local recurrence had disease progression with higher grade than previous

 

Dierselhuis et al Cochrane Database Sys Review 2019

- intralesional treatment versus wide resection for low grade / Grade 1 chondrosarcoma long bones

- 14 studies and 511 participants

- 419 treated with intralesional treatment, 91 with wide resection

- no difference in recurrence free survival

- lower complication rates and better functional outcomes with intralesional treatment

 

Hand

 

See boneschool page

 

Foot

 

Enchondroma foot 1Enchondroma foot 2