This tumor was once thought to be a cancer of a tendon sheath. It is now known to be a benign non-cancerous tumor of a tendon sheath. These masses are generally found on the toes, top of the foot or sides of the foot. They are always closely associated with a tendon sheath. They can also occur deep inside the foot. They slowly enlarge but never grow any larger than 4cm in size. They are firm irregular masses that are commonly painful. The pain seems to be a result of the tumor pressing firmly on the surrounding tissues and due to the interference with the function of the tendon the mass is growing from. As the tendon grows it can press so firmly on the bone it lays next to, that it can cause erosion of the bone. It is because of this erosion of bone that the tumor was once thought to be cancerous. Cancerous tumors can have the characteristic of invading bone through aggressive and destructive means. The erosion of the bone associated with giant cell tumors is due to pressure on the bone and not due to the invasion of the bone by the tumor. Other common soft tissues masses that may occur in the foot are ganglions, fibromas.
The diagnosis of a giant cell tumor is generally made by a pathologist following removal of the mass. Clinical history of the mass may give the surgeon an idea of what they might expect when removing the mass. X-rays may show the shadow of the mass, and in 10-20% of the cases, may demonstrate bone erosion. The mass is firm and nodular, and always connected to a tendon. A MRI may be useful in determining the extent or size of the mass.
Treatment of giant cell tumors is the excision of the tumor. Some physicians may attempt to inject the mass with cortisone in an attempt to shrink the mass.
The surgical excision of giant cell tumors is generally preformed in an out patient surgery center. Depending on the location of the mass the surgery may be preformed under a local anesthesia, with intravenous sedation or general anesthesia. Following administration of the anesthesia an incision is placed over the mass. The mass is then carefully dissected free from the surrounding soft tissues. Following the closure of the surgical site a gauze compressive dressing is applied. Depending upon the location of the mass the surgeon may apply a splint or below the knee cast. In some instances the surgeon may prefer that the patient use crutches for a few days or for as long as three weeks.
The recovery period depends upon the location of the mass and the extent of the soft tissue dissection necessary to remove the mass. The sutures are left in place for 10 – 14 days. During this period of time the patient should limit their activities and keep the foot elevated above their heart. It is also important to keep the bandage in place and keep the surgical site dry. If the patient has been instructed to wear a removable cast or use crutches it is important that they follow the surgeons instructions. Time off from work will depend upon the level of activity required of the job and the shoes necessary for work. Generally a minimum of one week off from work is necessary. If the patient can return to work while wearing a cast and they are allowed to perform light duty they may be able to return to work after one week.
The surgery is generally successful and without complications. However, as with any surgical procedure there are potential complications. Possible complications include, infection, excessive swelling, delays in healing, tendon or nerve injury. Because the mass is a growth from a tendon, removal of the mass may require the excision of a portion of healthy tendon. This can weaken the tendon or cause scaring of the tendon. Additionally there may be small skin nerves in the area of the tumor that may have to be sacrificed when removing the mass. If this occurs there may be small areas of patchy numbness on the skin following the procedure. This is generally not a significant problem. On occasion a nerve may get bound down in scar tissue and cause pain following the surgery. Recurrence of the mass is also possible but generally not considered a complication of the procedure.