Hand CASE 21

CASE                               21                               

A 22-year-old patient presents after sustaining an injury to her finger during a softball game. She reports pain and swelling after the trauma, but she was asymptomatic prior to this incident. She went to an urgent care over the weekend and was placed in a splint. She was told that she has a “mass” and presents for further follow up. On physical examination, the digit is swollen and ecchymotic. Range of motion is limited by pain, but no malrotation or scissoring of the digits with flexion is noted. An x-ray shows a radiolucent intramedullary lesion in the central metaphysis of the proximal phalanx with a transverse nondisplaced fracture through the lesion.

What is the most likely diagnosis of the tumor?

1. Aneurysmal bone cyst

2. Enchondroma

3. Giant cell tumor

4. Fibrous cortical defect

5. Osteoid osteoma

Discussion

The correct answer is (B). Enchondromas are the most common skeletal lesions of the bones of the hand. It is a frequent cause of pathologic fracture. It is asymptomatic prior to fracture, often found in adolescents and young adults, and is located in the central metaphysis.

What is the next step of treatment?

1. Closed reduction and percutaneous pinning of the fracture

2. Curettage and bone grafting of the tumor

3. Splinting the finger

4. Observation with serial radiographs

5. Oncologic ray resection

 

Discussion

The correct answer is (C). A nondisplaced pathologic fracture through an enchondroma is allowed to heal with closed treatment. At a later time after the fracture has healed, the enchondroma can be treated definitively with curettage and bone grafting.

The patient wants to know what caused this lesion. What do you tell her?

1. The normal ossification of the growth plate was disrupted and the central growth plate became dysplastic

2. Over proliferation of osteoclasts

3. As the bone grew, a defect in the bone filled with fluid

4. Over proliferation of the joint hyaline cartilage eroded into the bone

5. Degeneration of normal bone with immature bone

 

Discussion

The correct answer is (A). Over proliferation of osteoclasts is associated with giant cell tumor. Unicameral bone cysts are thought to be due to a bone defect filling with fluid. Degeneration of normal bone to immature bone is associated with fibrous dysplasia.

The patient’s fracture was treated successfully with immobilization. She presents 6 months later for definitive treatment. During informed consent for curettage and bone grafting, the patient wants to know the risk of malignancy.

What do you tell her?

1. 0%

2. 1% to 2%

3. 10%

4. 25%

5. 100%

 

Discussion

The correct answer is (B). When associated with multiple enchondromas, also known as enchondromatosis (Ollier disease), the risk is 10% to 25%. When associated with Mafucci syndrome (multiple enchondromas and venous malformations), the risk is near 100%. When the lesion is isolated, the risk is 1% to 2%.

 

Objectives: Did you learn...?

 

 

 

Treat an enchondroma with a pathologic fracture? Describe the presentation and etiology of enchondroma? Identify the risk of malignant degeneration?