Spinal Cord Cancer (Lymphoma of the Spinal Cord)

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What is Spinal Cord Cancer?

Cancers of the spinal cord may be of the Lymphoma type.

The spinal cord forms part of the central nervous system. It is a cylindrical continuation of the brainstem, commencing from the medulla (at the level of the foramen magnum at the base of the skull) and extending to the conus medullaris at the level of the L2 vertebra. It is located within the vertebral canal - the bony tube formed by the vertebral foramina. Below the level of L2, the remaining contents of the spinal canal are known as the cauda equina, the bundle of nerve rootlets in the subarachnoid space. Within the vertebral canal run the spinal cord, the spinal meninges, the cerebrospinal fluid, associated vessels and loose connective and fatty tissue.

Arising from the spinal cord are 31 pairs of spinal nerves that are the neural connections between the peripheries and the central nervous system. They attach to the spinal cord through ventral and dorsal roots and have both afferent and efferent properties. That is, the spinal cord acts as the main pathway for communication between the brain and the rest of the body.

Tumours of the spinal cord can be either primary or metastatic. The vast majority of spinal cord tumours are metastatic deposits from other primary sites. Tumours of the spinal cord can be divided into three groups, based on the anatomical location of the tumour mass.

Firstly, they are divided by their relationship to the spinal meninges, with tumours being classified as intradural or extradural. Furthermore, intradural tumours can be subdivided into those arising within the substance of the spinal cord itself - intramedullary tumours - or those arising in the subarachnoid space (extramedullary).

Extradural tumours most commonly represent metastases and usually arise within the vertebral bodies. These tumours most commonly cause spinal compression through extrinsic mass effect but can on occasion do so through intradural invasion. Symptoms from these tumours tend to be the slowly progressing features of spinal cord compression with initial predominantly motor loss followed by progressive sphincter dysfunction and ascending sensory loss. Extradural tumours represent the vast majority of spinal cord tumours.

Intradural extramedullary tumours tend to be nerve sheath tumours (neurofibromas) or meningiomas. They commonly present with nerve root involvement consisting of pain and progressive dysfunction due to spinal cord compression from the expanding tumour mass.

Intramedullary tumours usually represent gliomas ependymomas or astrocytomas, but metastatic deposits within the spinal cord itself are being increasingly recognised. These tumours result in a diffuse swelling of the spinal cord, often over several segments, characterised by loss of local function, pain and eventual loss of spinal cord function below the level of the lesion. A cyst may form in the spinal medulla, giving rise to a clinical picture of syringomyelia (predominant loss of spinothalamic function pain and temperature sensation - and blunted reflexes at the level of the lesion). Sacral sparing is a very late feature of intramedullary tumours but is pathognomonic.

The image shown above right is of an MRI scan that illustrates multiple vertabral metastases causing spinal cord compression.

Who gets Spinal Cord Cancer?

Lymphoma of the Spinal Cord is rare. Lymphoma of the spinal cord most commonly represents metastatic disease but can occasionally occur as a primary malignancy. Primary spinal lymphoma represents less than 1% of all CNS (central nervous system) lymphoma and occurs with increasing age with sex incidence being approximately equal.

Geographically, the tumour is found worldwide.

Predisposing Factors

Predisposing factors in the development of primary central nervous system lymphoma centre around immunodeficiency (including AIDS and following organ transplantation) when the disease can occur with increased incidence in younger patients. Sporadic cases of primary CNS lymphoma have been found in association with other diseases.

Progression

This type of tumour spreads by infiltration of the cerebrospinal fluid and seeding within the central nervous system. In less than 10% of patients distant metastases occur to sites such as the viscera, bones and soft tissues.

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