What Are Paraneoplastic Syndromes?

Paraneoplastic syndrome refers to the abnormal immune response (including cross-immunity, autoimmunity, and immune complex deposition, etc.) or other unknown causes due to abnormal tumor products (including the production of ectopic hormones), which can cause endocrine, neurological, Hematopoietic, bone, joint, kidney, and skin system lesions occur, and corresponding clinical manifestations appear. These manifestations are not directly caused by the location of the primary tumor or metastasis, but are indirectly caused by the above-mentioned pathways, so they are called paraneoplastic syndromes.

Paraneoplastic syndrome

Neurology

Paraneoplastic syndromes

1. Paraneoplastic lesions can affect any part of the nervous system such as the brain, spinal cord, peripheral nerves, neuromuscular junctions, and muscles. There are more than 10 types of paraneoplastic syndromes, which show different clinical symptoms and signs depending on the damaged part. Paraneoplastic syndromes can be divided into:
(1) Involved

Croft reported 1465 patients with tumors. 6.6% of patients had distal limb weakness or mild peripheral neuropathy, and the incidence was higher when combined with electrophysiology. Patients with small cell lung cancer and ovarian tumors have a higher incidence of PNS lesions. Lambert-Eaton myasthenic syndrome occurs in 2% to 5% of patients with small cell lung cancer. One-third of patients with subacute cerebellar degeneration have underlying lung cancer.
The cause of paraneoplastic syndrome is not very clear. It was previously believed that cancerous substances such as hormone-like substances and hormone-like substances that may directly damage the nervous system may be secreted due to cancer.

Exploring the pathogenesis helps to clarify the pathogenesis of autoimmune diseases and tumor immunology. The relevant pathogenesis has the following hypotheses:
1. Antibody-mediated theory Wilkinson (1964) described that the presence of autoantibodies in the serum of patients with neuromuscular tumors has proven myelomatic

Diagnosis: Paraneoplastic syndrome is mainly based on the patient's clinical manifestations and related antibody tests. No primary tumor is easily misdiagnosed before, and patients with persistent neurological symptoms are difficult to explain. PNS should be suspected. Vigilance is especially important.
Some patients with PNS have characteristic manifestations, such as PCD, POM, and Lambert-Eaton syndrome, which are often suggested to be related to tumors. If no cancer is found by systemic examination, regular review is required. Cerebrospinal fluid and electrophysiological examinations are helpful for diagnosis, and serum or CSF-specific autoantibodies can confirm PNS and suggest underlying tumor properties.

1. Serum and CSF immunological examination.
2. Routine examination of hematuria.
Other auxiliary checks:
Nervous system

Note the identification of primary diseases of the nervous system.

There are no specific therapies for PNS. Plasma exchange, vitamins, corticosteroids, and immunosuppressants can be tried. The efficacy has not been confirmed. In some patients, the symptoms of PNS are significantly relieved after treatment of the primary tumor. Early diagnosis and treatment of the syndrome can relieve symptoms in some patients, and early detection of potential tumors for early treatment can improve patients' quality of life and prolong life.

Paraneoplastic syndromes can affect many tissues and organs in the body and cause corresponding clinical manifestations, such as arthritis, rash, and endocrine disorders.

Prognosis: It is related to the prognosis of systemic tumors leading to this syndrome, and also to the location and extent of neurological damage. The prognosis varies.
Prevention: Early detection and early treatment.

The incidence of paraneoplastic syndromes of the central nervous system is relatively low, which is rarer than HL_v ? _? @ Z_ metastases, about 1% to 2%. The incidence of various paraneoplastic syndromes is unknown. The main reason is that PNS symptoms occur before the tumor is found. Some patients have only mild or asymptomatic symptoms, and auxiliary examinations such as electrophysiology have found abnormalities.

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