Definition: Paraneoplastic syndromes are disorders triggered by an abnormal immune system in response to the presence of a tumor.
They are non-metastatic effects that bother the entire body system even though the cancer is in only one area.
The frequency of the paraneoplastic syndrome is only around 10 to 20 percent of all malignant tumors. Neurological paraneoplastic syndromes account for about 1 percent in people with cancer. The incidence of morbidity and mortality of these syndromes are not completely known, since there is no predilection to certain races, sex or ages of people.
The symptoms can be hematological, gastrointestinal, cutaneous, cardiovascular, muscular or renal. Fever is the most common symptom in this type of syndrome but there may be many more.
The causes of paraneoplastic syndromes are not known. Doctors believe that there are pyrogens that trigger fever and alterations in the metabolism of copper and zinc producing a bad taste in the mouth.
Weight loss is considered to be due to bioactive molecules secreted by tumor osteoarthritic symptoms and appear to be related to growth hormone. Autoimmune diseases can be related to the production of antinuclear antibodies (ANA) that attack the connective tissue. Elevated levels of erythropoietin seem to be related to the development of a high red blood cell count. Anemia can be the result of internal hemorrhages and altered absorption of vitamins that contribute to the synthesis of red blood cells.
The diagnosis of a paraneoplastic syndrome can be difficult to perform, since it can mimic many other diseases so the index of suspicion must be high for the presence of cancers related to this syndrome. Certain liver enzymes may be elevated in this pathology, there may be no increase in albumin in the cerebrospinal fluid or in the globulins, the tumor markers may be elevated and the autoantibodies may be detected in the blood or tissue, where most will be directed towards the neural tissue.
Imaging studies can look for the presence of the tumor in a paraneoplastic syndrome, such as computed tomography or whole body MRI. Metastases can also be found. Tissue biopsies can show the type of cancer in the body, which can be done with an ultrasound-guided endoscopy or needle biopsy.
The treatment of paraneoplastic syndromes begins with the management of the underlying cancer. All the same treatment protocols are identified and used if there is a paraneoplastic syndrome associated with cancer. Immunosuppressive agents are used as long as it is an autoimmune disease that works together with cancer.
Surgical treatment is directed to the underlying tumor. Some can be resolved without removing the tumor, but this is not common. The extraction of the thymus gland is removed in certain paraneoplastic syndromes, such as myasthenia gravis.