Paraneoplastic syndrome

A paraneoplastic syndrome is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. These phenomena are mediated by humoral factors (by hormones or cytokines) excreted by tumor cells or by an immune response against the tumor. Sometimes the symptoms of paraneoplastic syndromes show even before the diagnosis of a malignancy.

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Classification

Paraneoplastic syndromes can be divided into 4 main categories:

• mucocutaneous paraneoplastic syndromes ^[1]
  • Dermatomyositis (25-50% of adult patients have an underlying malignancy) and polymyositis
  • Stiff person syndrome (SPS)
  • Leser-Trélat sign, a sudden onset of many pigmented skin lesions

• neurological paraneoplastic syndromes ^[2]
  • Paraneoplastic cerebellar degeneration associated with lung, ovarian, breast, lymphatic, and other cancers
  • Encephalomyelitis (inflammation of the brain and spinal cord)
  • Myasthenia gravis
  • Limbic encephalitis
  • Brainstem encephalitis
  • Neuromyotonia
  • Opsoclonus (involving eye movement)
  • Sensory neuropathy

• hematological paraneoplastic syndromes ^[3]
  • Granulocytosis (increased granulocytes) due to the production of G-CSF

• endocrine metabolic syndromes^[4]
  • Hypercalcaemia in breast cancer and lung cancer (typically squamous cell) due to the production of PTHrP (Parathyroid hormone-related protein)
  • SIADH associated w/ lung and CNS malignancies, typically small cell.
  • Ectopic ACTH secretion associated with small-cell lung cancer, carcinoid tumour, thymoma and other cancers

• others that may not fit into any of the above categories include:
  • Lambert-Eaton myasthenic syndrome (LEMS) in small-cell lung cancer
  • Membranous glomerulonephritis

Neurological

A particularly devastating form of paraneoplastic syndromes is a group of disorders classified as paraneoplastic neurological disorders (PNDs).^[5] These paraneoplastic disorders affect the brain and central nervous system and they are degenerative. Symptoms of paraneoplastic neurological disorders include ataxia (difficulty with walking and balance), dizziness, nystagmus (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, sensory loss in the limbs.

The most common cancers associated with paraneoplastic neurological disorders are breast, ovarian and lung cancer, but many other cancers have been linked to PNDs as well.

Treatment options include:

1. Therapies to eliminate the underlying cancer such as chemotherapy, radiation and surgery, and
2. Therapies to reduce or slow neurological degeneration. Rapid diagnosis and treatment is 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, it is important that PND patients consult with a specialist with experience in diagnosing and treating paraneoplastic neurological disorders.

Organizations

The International Paraneoplastic Association (IPA) is an organization dedicated to providing support and information to those affected by paraneoplastic neurological disorders.

References

1. ^ Cohen PR, Kurzrock R (1997). "Mucocutaneous paraneoplastic syndromes". Semin. Oncol. 24 (3): 334-59. PMID 9208889.
2. ^ MeSH Nervous+system+paraneoplastic+syndromes
3. ^ Staszewski H (1997). "Hematological paraneoplastic syndromes". Semin. Oncol. 24 (3): 329-33. PMID 9208888.
4. ^ MeSH Paraneoplastic+endocrine+syndromes
5. ^ Rees JH (2004). "Paraneoplastic syndromes: when to suspect, how to confirm, and how to manage". J. Neurol. Neurosurg. Psychiatr. 75 Suppl 2: ii43-50. PMID 15146039.

• http://www.antibodypatterns.com/hu.php

• IPA website