A spinal hemangioma is a common type of benign vascular growth affecting the vertebrae, the bones that make up the spine. These growths are an abnormal collection of blood vessels within the bone tissue, representing the most frequent non-cancerous tumor found in the spine. Present in about 10% of the population, the majority of people who have them never experience symptoms. These lesions are frequently discovered by chance during imaging for an unrelated condition.
Defining Spinal Hemangiomas
Spinal hemangiomas develop within the vertebral bodies. These growths are characterized by an overgrowth of thin-walled blood vessels, or vascular tissue, interspersed with bone marrow and fatty tissue. The lesions are slow-growing and are classified as either cavernous or capillary, depending on the structure of the blood vessels involved.
The majority of these vascular lesions are found in the middle and lower back, specifically the thoracic and lumbar regions. A typical hemangioma causes the horizontal bony supports within the vertebra to deteriorate while the vertical supports thicken, creating a striated or “corduroy” appearance on imaging. Most people are unaware of its presence because the lesions do not expand beyond the bone or affect nearby nerves.
Understanding the Underlying Causes
The precise cause of spinal hemangiomas remains largely unknown, which is why they are often described as idiopathic. Scientists consider these lesions to be a type of vascular malformation, likely originating from an error in the development of blood vessels early in life. This suggests the growths are congenital, or present from birth, even if they are not detected until adulthood.
One prominent theory suggests a developmental anomaly occurs during the embryonic formation of the spine and its associated vascular structures. This abnormal vascular growth, sometimes linked to gene variations, leads to the disorganized collection of vessels that form the hemangioma. Genetic factors may also play a role, as a predisposition for vascular malformations can sometimes be inherited. However, a single, definitive gene responsible for the common vertebral hemangioma has not been isolated.
Hormonal influences are another factor scientists consider, particularly regarding the growth and enlargement of existing hemangiomas. These lesions are more commonly diagnosed in females, which hints at a potential role for hormones like estrogen and progesterone. Changes in hormone levels, such as those during pregnancy, have been observed to occasionally lead to the rapid expansion of a previously quiet hemangioma.
How Spinal Hemangiomas Present
The vast majority of spinal hemangiomas are asymptomatic, producing no noticeable symptoms. Less than 5% of all spinal hemangiomas ever cause problems that require medical attention. When symptoms do occur, they are generally attributed to the rare instance of an aggressive lesion that grows larger and extends outside the vertebral bone.
The most common symptom in these rare cases is localized back pain at the site of the lesion. Pain can also radiate along a nerve pathway (radicular pain) if the hemangioma expands to compress a spinal nerve root. In the most severe scenarios, the tumor can grow into the spinal canal, leading to compression of the spinal cord itself. This can result in neurological deficits such as muscle weakness, numbness, tingling in the limbs, or difficulty walking.
The vascular growth can sometimes weaken the bone structure of the vertebra, making it susceptible to a vertebral compression fracture. This painful event can occur with minimal trauma and can further contribute to spinal cord or nerve compression. Aggressive hemangiomas that cause neurological issues are most frequently found in the thoracic spine (mid-back).
Diagnosis and Treatment Approaches
Diagnosis is primarily achieved through medical imaging, as most lesions are discovered incidentally during scans performed for other reasons. Magnetic Resonance Imaging (MRI) is highly effective, providing detailed images that assess the extent of the lesion and potential compression of the spinal cord or nerve roots. Computed Tomography (CT) scans are also valuable, as they clearly show characteristic structural changes in the bone, such as the “polka-dot” appearance of the vertebra.
For the vast majority of asymptomatic spinal hemangiomas, the management approach is observation with no immediate treatment required. The patient is monitored over time with periodic imaging to ensure the lesion remains stable. Treatment is reserved for the small percentage of cases that are symptomatic or show signs of aggressive growth.
A common treatment for painful hemangiomas that have weakened the bone is vertebroplasty or kyphoplasty. These procedures involve injecting surgical bone cement into the vertebra to stabilize it and relieve pain. Other options include radiation therapy to shrink the tumor, or embolization, a minimally invasive procedure to cut off the blood supply to the lesion. Surgical removal is usually reserved for the most severe cases involving significant neurological compromise due to spinal cord compression.