Solitary bone plasmacytoma is a bone tumor that arises from plasma cells. Plasmacytomas can occur in any bone, but they are most common in the spine. At the Spine Hospital at the Neurological Institute of New York, we specialize in spinal plasmacytomas.
When people discuss plasmacytomas, they discuss three of the body’s systems. The first is the immune system. Normal plasma cells play an important role in the immune system. The second system is the blood. Plasma cells are a type of white blood cells. The third is the bone. Plasma cells (and all other blood cells) are made in the bone marrow.
Solitary bone plasmacytomas, then, arise in bones. They develop from abnormal plasma cells (blood cells) in the bone marrow.
Plasmacytoma is a rare disorder.
Spinal plasmacytomas may cause dull, aching pain as they destroy normal bone. If a vertebra is sufficiently weakened by the plasmacytoma, a painful compression fracture may result.
Spinal plasmacytomas may cause other symptoms that vary depending on the tumor’s size and location. As they grow, spinal plasmacytomas may compress nearby nerve roots or the spinal cord, damaging these delicate tissues. Compression of nerve roots may cause pain that radiates to the arms or legs. Spinal cord compression may cause pain, weakness, numbness, or clumsiness in the arms and legs. In some cases, spinal cord compression may result in a loss of bowel or bladder control.
Causes and Risk Factors
The exact causes of solitary bone plasmacytoma are not known.
Solitary bone plasmacytomas are more common in men than women, and usually occur in individuals in the fourth to sixth decades of life. They are most common in people with African-American ancestry, and least common in people with ancestors from Asia and the Pacific Islands.
Tests and Diagnosis
A single plasmacytoma may be diagnosed with the following tests:
- X-ray (also known as plain films) –test that uses invisible electromagnetic energy beams (X-rays) to produce images of bones. Soft tissue structures such as the spinal cord, spinal nerves, the disc and ligaments are usually not seen on X-rays, nor on most tumors, vascular malformations, or cysts. X-rays provide an overall assessment of the bone anatomy as well as the curvature and alignment of the vertebral column. Spinal dislocation or slippage (also known as spondylolisthesis), kyphosis, scoliosis, as well as local and overall spine balance can be assessed with X-rays. Specific bony abnormalities such as bone spurs, disc space narrowing, vertebral body fracture, collapse or erosion can also be identified on plain film X-rays. Dynamic, or flexion/extension X-rays (X-rays that show the spine in motion) may be obtained to see if there is any abnormal or excessive movement or instability in the spine at the affected levels.
- CT scan: a procedure that uses a combination of X-rays and computer technology to produce detailed images of the body. CT scans are more detailed than general X-rays.
- MR scan: a procedure that uses a combination of large magnets, radio waves, and a computer to produce detailed images of organs and structures inside the body. Also called an MRI, for magnetic resonance imaging.
- Blood test: a procedure in which a sample of blood is withdrawn to be analyzed in a lab. A specific blood test called a serum protein electrophoresis can assist in the diagnosis of plasmacytoma.
However, other procedures also help with diagnoses. Bone marrow biopsies, procedures in which a small sample of bone marrow is withdrawn for analysis in a lab, can help establish that only a single tumor is present. Skeletal scans such as PET (positron emission tomography) can also help rule out other tumors.
Plasmacytoma may progress to multiple myeloma, a disease in which multiple tumors are present. Patients with solitary bone plasmacytoma will be regularly monitored for progression to multiple myeloma.
Most patients with spinal plasmacytoma can be effectively treated with radiation or chemotherapy. These treatments shrink the tumor gradually.
In some patients, however, urgent surgery may be needed for spinal cord decompression. In this type of surgery, the spinal cord is relieved of the harmful pressure placed on it by the plasmacytoma. Decompression surgery will usually halt the damage to the spinal cord. Symptoms will not worsen, and may improve. After decompression surgery, an instrumented fusion may be necessary to restore spinal stability.