Giant Cell Tumor

 

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Original Editors - Michael Fogarty from Bellarmine University's Pathophysiology of Complex Patient Problems project.

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Definition/Description

Giant cell tumors of the bone are benign multi-nucleated cell masses that are commonly found at the epiphyses and sometimes the metaphyses of long bones. These tumors get their name due to the large cell appearance they have when viewing them under a microscope.

Giant cell tumors are a discrete and locally aggressive abnormal growth or tumor that can metastasize to other areas of the body. The metastatic forms of giant cell tumors are known as malignant sarcomas, though this form of giant cell tumor is very rare.  Giant cell tumors of the bone are one of the most challenging benign bone tumors due to resulting substantial bone damage, local reoccurrence, lung metastasis, metastasis to lymph nodes, and malignant transformation.

Prevalence

Giant cell tumors of the bone are rare and occur in roughly one out of every million people per year.  In the united states 5% of all the primary bone tumors and 21% of all benign bone tumors present as a giant cell tumor.  Significantly higher incidence rates are observed in the Chinese population as compared to the western Caucasian population where giant cell tumors constitute up to 20% of the population being affected.

The most common incidence for giant cell tumors is in skeletally mature patients between the ages of 20 and 55, with the maximum occurrence in the third decade of life.  Females are more likely to develop giant cell tumors than males with a 1.3-1.5: 1 ratio.

These tumors most frequently involve the epiphyses ends of long bones with the femur, tibia, and distal radius most commonly involved..  The most common locations of occurrence are around the knee which is involved in 60% of cases, the distal radius which is involved in about 10-12% of cases, and the sacrum which is much more rare but still the third most common location of involvement.

Though metastasis to the lungs does occur it is very rare and only about 3% of cases will result in the tumor spreading to the lungs. When giant cells metastasize to the lung they appear as clusters that are located within the lung. Giant cell tumors metastasize at a slow rate and usually do not appear for 3-5 years after the patient has been diagnosed with their primary bone tumor, but this metastasis may go unidentified for up to 10 years or longer.

Characteristics/Clinical Presentation

Every patient is going to experience the signs and symptoms of a giant cell tumor slightly different, and many of the symptoms may depend on the locality of the tumor. The following are the most common signs and symptoms that a patient may present with:

• Pain in the area of the tumor that progressively increases
  
• Pain that increases with activity and decreases with rest
  
• Decreased joint range of motion
  
• Tender hard mass may be palpated
  
• Muscle atrophy
  
• Elevated temperature of the overlying skin
  
• Mass or swollen area (may or may not be painful) 

If significant bone destruction occurs at the tumor site and the cortex layer of the bone is damaged a pathological fracture may develop. If the tumor is in a weight bearing bone the patient may present with significant pain upon weight bearing.

When the sacrum is involved the patient may present with localized pain in the low back and sacrum that may radiate down one or both legs. Swelling may also be present in the location of the tumor. The patient may also state that they are experiencing abdominal discomfort and may present with neurological problems such as bowel and bladder dysfunction, sexual dysfunction, and numbness/weakness of the lower extremities.

Associated Co-morbidities

No associated co-morbidities were found to be related to giant cell tumor.

Medications

Bisphosphonates
This medication is not used as a cure for the giant cell tumor itself but is used instead to inhibit the osteolytic development of bone that is seem at the location of a giant cell tumor, they act by inhibiting osteoclastic bone resorption. Research indicates that bisphosphonates may be beneficial in managing disease advancement in giant cell tumors of bone and these agents have been found to directly inhibit the giant cell tumor.

Diagnostic Tests/Lab Tests/Lab Values

Giant cell tumors are usually diagnosed by x-rays and verified through histological evaluation with results that are typically found with the specific characteristics of giant cell tumors. Below is a list of diagnostic tests that may be utilized to help identify and distinguish the type of tumor that is present.

Biopsy of the Tumor: A sample of the tumor is removed and inspected under a microscope and allows the physician to determine the aggressiveness of the tumor. The cellular structure of the tumor is then examined to rule out other malignant tumors that may resemble a giant cell tumor.

X-rays: X-rays are diagnostic tests that are used to produce projections of radiographic images of bone tissues and other organ tissues onto film. Giant cell tumors appear as translucent lesions within the bone that are usually near the joint line. The section of the bone that is involved is surrounded by a slim border of white bone; the bone in the region of the tumor is occasionally protracted outward. Chest x-rays should be obtained at the diagnosis of the tumor as well as randomly during the follow-up to view for metastasis to the lung.

Magnetic Resonance Imaging: MRI’s are diagnostic tests that use powerful magnetic fields to produce detailed images of internal structures within the body. This imaging procedure will allow for more in depth assessment of the bone that is affected.

Computerized Tomography scan: A CT or CAT scan is a diagnostic imaging that uses a combination of computer processing and x-rays to generate cross sectional images of the body, they can also generate 3 dimensional images of the internal structure of the body. CT scans are more detailed than x-rays and can show imaging for bones, muscle, fat, and organs. CT scans are often performed in the lungs of patients with giant cell tumors to examine for signs of metastasis to the lung.

Bone scan: Bone scans are used to help diagnose if a tumor is present and if it has spread to other areas of the body. A bone scan will show up with a “hot spot” in the location of the bone where the tumor is present.

Complete blood count: Measures the size, number, and maturity of different blood cells in a precise quantity of blood.

Blood Tests: The blood tests taken include blood chemistries

Etiology/Causes

Giant cell tumors are believed to occur spontaneously with no known etiology. Though, “the tumor cells have been reported to produce chemoattractants that can attract osteoclasts and osteoclast precursors.” (pathology book) They have not been shown to be linked to factors such as trauma, environmental conditions, or diet though in rare cases they may be associated with hyperparathyroidism.

Systemic Involvement

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Medical Management (current best evidence)

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Physical Therapy Management (current best evidence)

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Alternative/Holistic Management (current best evidence)

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Differential Diagnosis

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Case Reports/ Case Studies

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Resources

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Recent Related Research (from Pubmed)

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References

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