A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of cancer in the body, but unlike mass effect, is not due to the local presence of cancer cells. In contrast, these phenomena are mediated by humoral factors (such as hormones or cytokines) excreted by tumor cells or by an immune response against the tumor.
Paraneoplastic syndromes are typical among middle-aged to older patients, and they most commonly present with cancers of the lung, breast, ovaries, or lymphatic system (a lymphoma). Sometimes, the symptoms of paraneoplastic syndromes show before the diagnosis of a malignancy, which has been hypothesized to relate to the disease pathogenesis. In this paradigm, tumor cells express tissue-restricted antigens (e.g., neuronal proteins), triggering an antitumor immune response which may be partially or, rarely, completely effective in suppressing tumor growth and symptoms. Patients then come to clinical attention when this tumor immune response breaks immune tolerance and begins to attack the normal tissue expressing that (e.g., neuronal) protein.
The abbreviation PNS is sometimes used for paraneoplastic syndrome, although it is used more often to refer to the peripheral nervous system.
Video Paraneoplastic syndrome
Classification
Paraneoplastic syndromes can be divided into four main categories: endocrine, neurological, mucocutaneous, and hematological paraneoplastic syndromes, as well as others that may not fit into any of the above categories:
Maps Paraneoplastic syndrome
Neurological
A specifically devastating form of paraneoplastic syndromes is a group of disorders classified as paraneoplastic neurological disorders (PNDs). These PNDs affect the central or peripheral nervous system; some are degenerative, though others (such as LEMS) may improve with treatment of the condition or the tumor. Symptoms of PNDs may include difficulty with walking and balance, dizziness, rapid uncontrolled eye movements, difficulty swallowing, loss of muscle tone, loss of fine motor coordination, slurred speech, memory loss, vision problems, sleep disturbances, dementia, seizures, and sensory loss in the limbs.
The most common cancers associated with PNDs are breast, ovarian, and lung cancers, but many other cancers can produce paraneoplastic symptoms, as well.
Treatment
Treatment options include:
- Therapies to eliminate the underlying cancer, such as chemotherapy, radiation and surgery
- Therapies to reduce or slow neurological degeneration: Rapid diagnosis and treatment are critical for the patient to have the best chance of recovery. Since these disorders are relatively rare, few doctors have seen or treated PNDs. Therefore, PND patients should consult with a specialist with experience in diagnosing and treating paraneoplastic neurological disorders.
References
Source of the article : Wikipedia
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