A 4-year-old boy presented to the paediatric orthopaedic clinic because of several months of painless swelling of the 4th finger of the right hand.
There was no previous history of trauma or infection.
On examination there were no movement restriction or inflammatory signs.
The hand radiograph (Fig. 1) shows 3 metaphyseal lytic lesions, with well-defined borders and a narrow zone of transition, centred in the medullary canal on the 4th ray of the right hand. There was bony enlargement and cortical thinning. Periosteal reaction was absent and no associated fractures were found.
Magnetic resonance imaging (Fig. 2) showed 3 lesions with signal intensity similar to physeal cartilage (high signal intensity on T2/PD FS and low signal intensity on T1), with peripheral and septal contrast uptake on T1 post gadolinium. No soft tissue component was noted.
Primary osseous tumours of the hand are rare (<5% of bone tumours) and enchondromas (benign cartilaginous tumours) account for most cases. [1] Enchondromas are usually asymptomatic; if pain is present a pathological fracture should be suspected.
On plain films or CT, enchondromas present as lucent lesions with a narrow zone of transition and well-defined margins, located in the medullary canal near the physis. Chondroid pattern of calcification may be seen. Endosteal cortical scalloping and thinning, and bone expansion can be present. [1, 2]
On MRI, enchondromas present high T2 signal intensity due to the high extracellular water content of cartilage. On T1WI, lobulated margins are apparent. On T1WI post-contrast, peripheral and septal enhancement patterns can be noted due to the lesion's avascular nature.
There are 3 syndromes associated with multiple enchondromas:
- Multiple enchondromatosis or Ollier's disease is the most common. It is a rare, sporadic disorder, characterized by the presence of asymmetrically distributed multiple enchondromas, with a mean age of diagnosis of 13 years of age. [1] The hands' small tubular bones are frequently affected (metacarpals more so than the phalanges). Enchondromas can result in deformity (e.g. limb shortening). Treatment is only considered when complications (deformity, fractures or malignant transformation) ensue.
- Maffucci syndrome is characterized by multiple enchondromas and soft tissue haemangiomas or lymphangiomas. It is sporadic and has a higher risk of malignant transformation into sarcoma.
- Metachondromatosis is inherited (autosomal dominant) and consists of multiple enchondromas and osteochondromas. Unlike typical osteochondromas, which point away from joints, these osteochondromas may point towards the joint. Osteochondromas are located in the digits and long bones, and regress spontaneously. Malignant transformation is rare. [4]
Chondrosarcoma is the most important differential diagnosis. A 5-50% risk of malignant transformation has been reported in Ollier's disease. [1] Malignant transformation is more frequent in long bones and the axial skeleton. Severe pain, lesion growth, destruction of the cortex or of existing calcification, and periosteal reaction are suspicious features. The mean age of malignant transformation is 33 years. There is a risk of developing multiple chondrosarcomas. [3] Differentiating chondrosarcomas from enchondromas is difficult. There is evidence that early exponential enhancement on MRI has high sensitivity but low specificity for malignancy. Only the absence of enhancement seems to exclude malignancy.
Macrodactyly results from the enlargement of all elements of a digit and is present in several syndromes. Proteus syndrome, a rare, sporadic multisystem disorder, can present with macrodactyly. Other findings have to be present for the diagnosis. [6]
Multiple encohondromatosis
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The patient (a child) has a persistent, painless swelling of the fourth finger on the right hand. The X-ray plain film shows a well-demarcated lucent area within the medullary cavity of the fourth finger’s phalanx, with some localized thinning of the cortex and mild expansion. No obvious pathological fracture or bony destruction is observed in the lesion range or adjacent joint regions.
MRI examination demonstrates that the lesion appears as a high signal on T2-weighted images, and on T1-weighted images the lesion edges are lobulated. Post-contrast enhancement suggests mild or thin-layer enhancement around the lesion and within its internal septa. No evident soft tissue swelling or joint involvement is observed.
Based on the child’s age, clinical presentation (painless swelling), and imaging findings (lucent lesion in the medullary cavity, well-defined margins, mild expansion, and peripheral enhancement), the following differential diagnoses may be considered:
Considering the child’s age, the specific site of the lesion (a small bone in the finger), clinical symptom (painless), and the imaging characteristics (a lucent area within the medullary cavity, cartilaginous high signal, well-defined margins, and no apparent bony destruction), the most likely diagnosis is enchondroma. If necessary, further follow-up or biopsy could be performed to rule out rare malignant possibilities.
For a solitary enchondroma with mild symptoms, conservative follow-up is generally recommended, with periodic imaging to monitor changes in the lesion. Surgical intervention (e.g., curettage and bone grafting) may be considered under the following circumstances:
Rehabilitation/Exercise Prescription Recommendation: For younger children with localized lesions and minimal pain, the main focus is on maintaining joint range of motion and functional exercises, while avoiding impact or heavy loading. Under the evaluation of a professional rehabilitation therapist, simple finger joint mobility and flexibility exercises can be gradually introduced. An example (following the FITT-VP principle) is as follows:
If the child has other systemic or skeletal developmental concerns, an orthopedic specialist should perform a comprehensive evaluation considering overall development to create an individualized rehabilitation plan. Throughout the rehabilitation process, ensure safety, gradual progression, and close monitoring for exacerbation of symptoms.
Disclaimer: This report is a comprehensive analysis based on the currently available information and is for reference only. It cannot replace an in-person consultation or a specialist’s final opinion. If you have any concerns or if symptoms worsen, please consult a qualified medical professional in a timely manner.
Multiple encohondromatosis
