Enchondroma

Enchondroma is a benign hyaline cartilage tumor occurring in the medulla of bones in adults and causing destruction of the cancellous bones.

It is also called chondromyxoma.

Tumor cell replaces the normal bone with mineralized or unmineralized hyaline cartilage.

Enchondroma has the potential to undergo malignant transformation, especially when situated in large bones, the pelvis.

Etiology

Jaffe postulated:

Enchondroma is a developmental disorder. It arises from embryonic nests or ‘nidi’ derived from epiphyseal plates which get displaced in metaphysics and lead to the formation of enchondroma or multiple enchondromatosis (If multiple physeal plates are affected)

Age Predisposition: 5-80 years (Mostly occurs in 3rd and 4th decades)

Male: Female = 1:1

Site: 50 % occurs in the hand

Enchondroma is the most common primary tumor of the hand. Proximal phalanx is the most common site.

Clinical Features of Enchondroma

Enchondroma is mostly asymptomatic

There is painless swelling/ Painful limitation of movement

Pain occurs due to pathological fracture/ Malignant transformation.

Enchondroma protuberances: Exophytic growth in metacarpals and phalanges.

Radiological Features of Enchondroma

There is a small, well-demarcated, lobulated translucent lesion with cortical thinning, bony expansions, and a variable amount of intralesional stippled calcification.

“Ring and Arcs ” like density

The cortex may be perforated and the shadow of the tumor may be extended to soft tissue although benign.

Usually < 6 cm in marginal length.

Pathological Features

Gross Features

There is lobulated and bluish-white translucent in appearance which can be seen white area of calcification.

Microscopic Features

There is the lobulated mass of hypocellular and avascular hyaline cartilages.

Treatment Options for Enchondroma

In the case of a benign (Small ) symptomatic lesion: No treatment is necessary

Large symptomatic lesions require intervention.

Surgery and Intralesional Currette is the treatment of choice

Extraosseous components if present should be excised.

Care during treatment should be given to prevent iatrogenic seeding of tumor cells in surrounding soft tissue.

Malignant Transformation :

• Hand: <1%
• Others: 2%-5%

Multiple Enchondromatosis is seen in Ollier’s disease, Mafucci’s syndrome, and Metachondromatosis. Malignant transformation is high in these lesions as malignant transformation depends upon the number of lesions.

In case of malignant transformation: Wide excision and Appropriate reconstruction like Chondrosarcoma.

See also: Radiograph of Bone Tumor

See also: Musculoskeletal Malignancy: Management