A hemangioma is a non-cancerous growth composed of a tangle of small, abnormal blood vessels. When this vascular lesion develops within the bony building blocks of the spine, known as the vertebrae, it is called a vertebral hemangioma. These growths are remarkably common, occurring in an estimated 10% to 12% of the general population, making them the most frequently encountered benign tumor of the spinal column. Most lesions are discovered accidentally during imaging tests performed for unrelated issues, raising questions about their origin and whether an injury might be responsible.
Understanding Vertebral Hemangiomas
A vertebral hemangioma is a vascular malformation located within the vertebral body, typically in the thoracic (mid-back) or lumbar (lower back) regions. This slow-growing collection of vessels displaces the normal bone marrow and can cause the bony structure, or trabeculae, to thicken and reorganize. The presence of abundant fat within the vascular spaces is a characteristic feature often seen on imaging.
These lesions are considered benign and stable, rarely causing symptoms. Because they rarely cause symptoms, most people are unaware they have one throughout their lives. Only a small fraction, estimated at less than 5%, ever grow large enough or behave aggressively enough to warrant medical attention.
Addressing the Role of Trauma in Formation
The established scientific consensus is that vertebral hemangiomas are developmental or congenital in origin, meaning they form early in life. They are classified as hamartomatous lesions, arising from an abnormal mix of tissue components, rather than being caused by external factors like injury. Researchers believe a genetic or hereditary predisposition is the likeliest cause for their formation.
Acute trauma, such as a fall or a car accident, does not cause the formation of the hemangioma itself. However, a significant traumatic event can be directly linked to the discovery of a pre-existing hemangioma. Trauma can cause the already weakened, vascular-rich bone to bleed, swell, or fracture, making the previously silent lesion painful and detectable. The trauma acts as a symptomatic trigger, forcing the patient to seek medical imaging.
When Do They Become Symptomatic?
A symptomatic hemangioma is referred to as an aggressive lesion, occurring in about 1% of cases. These lesions typically cause problems through two main mechanisms related to their growth and location.
Structural Weakening
One mechanism involves the expansion of the hemangioma within the vertebral body, which structurally weakens the bone. This process can lead to a painful pathological compression fracture, where the vertebra collapses under normal axial load.
Neural Compression
The second mechanism is the lesion’s expansion into the spinal canal or the neural arch, which houses the spinal cord and nerve roots. This encroachment compresses the neural tissues, leading to neurological symptoms. These symptoms can manifest as localized back pain, radiating pain (radiculopathy), numbness, tingling, or muscle weakness. Any new or progressive neurological deficit, such as difficulty walking or changes in bowel or bladder function, requires immediate medical evaluation.
Diagnosis and Treatment Options
Diagnosis typically begins with advanced imaging, with Magnetic Resonance Imaging (MRI) being the preferred tool. MRI is effective at visualizing the soft tissue components of the lesion and determining if it has extended into the spinal canal to compress the nerves. A Computed Tomography (CT) scan is used as a supplement, as it clearly shows characteristic bone changes, such as thickened vertical bony striations.
For the majority of patients with asymptomatic hemangiomas, no active treatment is required, and management involves watchful waiting. This includes periodic monitoring with imaging to ensure the lesion remains stable. When a lesion becomes symptomatic or aggressive, treatment focuses on relieving pain and preventing neurological damage.
Intervention options include percutaneous vertebroplasty, which involves injecting medical-grade cement into the damaged vertebra to stabilize it and prevent further collapse. Another technique is transarterial embolization, where the blood supply to the tumor is blocked to reduce its size and vascularity. In cases involving significant spinal cord compression or intractable pain, surgical resection may be necessary to remove the compromised bone and decompress the neural structures.