Prostate cancer is the second most common urological malignancy to be associated with paraneoplastic syndromes after renal cell carcinoma. Paraneoplastic syndromes of this nature tend to occur in the setting of late stage and aggressive tumors with poor overall outcomes (endocrine manifestations, neurological entities, dermatological conditions, and other syndromes). A vast majority of prostate cancer cases (over 70%) document paraneoplastic syndrome as a major clinical manifestation of prostate cancer; and interestingly (under 20%), the syndrome as an initial sign of disease progression to the castrate-resistant state. Urologist researchers identify serum markers that are associated with the syndrome in order to specific what type of therapies may work most effectively.

Paraneoplastic neurological syndromes may be related immune checkpoint inhibitors (ICIs), one of the underlying causes in inflammatory central nervous system diseases (CNS). The central idea around such research pinpoints treatment strategies to combat cancer related outcomes in the clinical arena, specifically ICIs. Research suggests that patients who are treated with ICIs are more susceptible to CNS disease (since the mechanism of ICIs induces adverse effects on the CNS due to augmented immune responses and neurotoxicity). The purpose of this exploration was to shed light on immunotherapies and distinguishing between neurotoxicity and brain metastasis in the early stages of treatment. In other research, scientists have found that paraneoplastic peripheral nerve disorders (autoantibodies linked to multifocal motor neuropathy) may provide important clinical manifestations. This is especially important for patients who experience inflammatory neuropathies since solid tumors are often associated with peripheral nerve disorders. CV2 autoantibodies, which target dihydropyriminase-related protein 5 (DRP5, or CRMP5) are also associated with a variety of paraneoplastic neurological syndromes, including sensorimotor polyneuropathies. Interestingly, patients undergoing immune therapies or tumor removal respond very well to antibodies that target CASPR2 (to treat nerve hyperexcitability and neuromyotonia).

In the case of paraneoplastic Cushing's syndrome arising from a small cel carcinoma of the endometrium, paraneoplastic syndrome has been seen to interfere with standard treatments and lead to unexpected complications and clinical course. The purpose of this clinical case demonstrates the aggressive nature of the neuroendocrine small cell carcinoma with rapid invasion and extra-uterine spread. The researchers raise recognition for timely recognition of paraneoplastic syndrome, which in this particular case use a combinatorial therapy of etoposide and cisplatin chemotherapy to save the 32-year old female patient's life (presented with persistent migraine-like headache, palpitations, progressive nausea and vomiting, photo- and sonobia, menometrorrhagia and concomitant general fatigue).

Treatment options include:

1. Therapies to eliminate the underlying cancer, such as chemotherapy, radiation and surgery.

2. Therapies to reduce or slow neurological degeneration. In this scenario, 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 paraneoplastic neurological disorders (PNDs). Therefore, PND patients should consult with a specialist with experience in diagnosing and treating paraneoplastic neurological disorders.

A specific prognosis for those afflicted with paraneoplastic syndromes links to each unique case presented. Thus, prognosis for paraneoplastic syndromes may vary greatly. For example, paraneoplastic pemphigus often included infection as a major cause of death. Paraneoplastic pemphigus is one of the three major subtypes that affects IgG autoantibodies that are characteristically raised against desmoglein 1 and desmoglein 3 (which are cell-cell adhesion molecules found in desmosomes). Underlying cancer or irreversible system impairment, seen in acute heart failure or kidney failure, may result in death as well.

As reported by Dispenzieri "et al." Mayo Clinic treatment regimens are tailored to treat the clinical manifestations and prognosis for the rate of progression of the POEMS syndrome in each patient. In rare cases, patients may have minimal or no symptoms at presentation or after successful treatment of their disorder. These patients may be monitored every 2–3 months for symptoms and disease progression. Otherwise, treatment is divided based on the local versus systemic spread of its clonal plasma cells. Patients with one or two plasmacytoma bone lesions and no clonal plasma cells in their bone marrow biopsy specimens are treated by surgical removal or radiotherapy of their tumors. These treatments can relieve many of the syndromes clinical manifestations including neuropathies, have a 10-year overall survival of 70% and a 6-year progression-free survival of 62%. Patients with >2 plasmacytoma bone lesions and/or increases in bone marrow clonal plasma cells are treated with a low-dose or high-dose chemotherapy regimen, i.e. a corticosteroid such as dexamethasone plus an alkylating agents such as melphalan. Dosage regimens are selected on the basis of patient tolerance. Hematological response rates to the dexamethasone/melphalan regimens have been reported to be in the 80% range with neurological response rates approaching 100%. Patients successfully treated with the high-dose dexamethasone/melphalan regimen have been further treated with autologous stem cell transplantation. In 59 patients treated with the chemotherapy/transplantation regimen, the Mayo Clinic reported progression-free survival rates of 98%, 94%, and 75% at 1, 2, and 5 years, respectively.

Other treatment regiments are being studied. Immunomodulatory imide drugs such as thalidomide and lenalidomide have been used in combination with dexamethasone to treat POEMS syndrome patients. While the mechanism of action fo these immunomodulators are not clear, they do inhibit the production of cytokines suspected of contributing to POEMS syndrome such as VEGF, TNFα, and IL-6 and stimulate T cells and NK cells to increase their production of interferon gamma and interleukin 2 (see immunomodulatory imide drug's mechanism of action). A double blind study of 25 POEMS syndrome patients found significantly better results (VEGF reduction, neuromuscular function improvement, quality of life improvement) in patients treated with thalidomide plus dexamethasone compared to patients treated with a thalidomide placebo plus dexamethasone.

Since VEGF plays a central role in the symptoms of POEMS syndrome, some have tried bevacizumab, a monoclonal antibody directed against VEGF. While some reports were positive, others have reported capillary leak syndrome suspected to be the result of overly rapid lowering of VEGF levels. It therefore remains doubtful as to whether this will become part of standard treatment for POEMS syndrome.

For symptomatic relief of carcinoid syndrome:

- Octreotide (a somatostatin analogue which decreases the secretion of serotonin by the tumor and, secondarily, decreases the breakdown product of serotonin (5-HIAA))

- Telotristat ethyl (Xermelo) along with a somatostatin analogue in patients not responding to somatostatin analogue monotherapy. It is a tryptophan hydroxylase inhibitor and reduces the production of serotonin.

- Peptide receptor radionuclide therapy (PRRT) with lutetium-177, yttrium-90 or indium-111 labeled to octreotate is highly effective

- Methysergide maleate (antiserotonin agent but not used because of the serious side effect of retroperitoneal fibrosis)

- Cyproheptadine (an antihistamine drug with antiserotonergic effects)

Alternative treatment for qualifying candidates:

- Surgical resection of tumor and chemotherapy (5-FU and doxorubicin)

- Endovascular, chemoembolization, targeted chemotherapy directly delivered to the liver through special catheters mixed with embolic beads (particles that block blood vessels), used for patients with liver metastases.

Disease progression is difficult to ascertain because the disease can metastasize anywhere in the body and can be too small to identify with any current technology. Markers of the condition such as chromogranin-A are imperfect indicators of disease progression.

The anti-Purkinje cell antibodies originally described in PCD led to the hypothesis that the antibody might be pathogenic, much as earlier studies had demonstrated pathogenicity of anti-acetylcholine receptor antibodies in myasthenia gravis. However, when the antibody was used to clone the cDNA encoding the cdr2 antigen, it was found to be an intracellular protein. This led to the suggestion that there might be a cell-mediated component (T cell) in disease pathogenesis. cdr2 antigen-specific CD8+ T cells were subsequently described in more anti-Yo-positive PCD patients. These T cells are likely components in both the anti-tumor immune response and in the neuronal degeneration.

Paraneoplastic cerebellar degeneration (PCD) is a paraneoplastic syndrome associated with a broad variety of tumors including lung cancer, ovarian cancer, breast cancer, Hodgkin’s lymphoma and others. PCD is a rare condition that occurs in less than 1% of cancer patients.

As is the case with other paraneoplastic syndromes, PCD is believed to be due to an autoimmune reaction targeted against components of the central nervous system, mostly to Purkinje cells.

It is thought to be triggered when tumor cells (in PCD, most commonly ovarian or breast cancer) ectopically express proteins normally expressed in the cerebellum. This is believed to trigger an anti-tumor immune response that may be clinically significant, but also an anti-neural immune response. A broad spectrum of neuronal and glial proteins has been identified as target antigens in PCD.

Neurological symptoms may include, among others, dysarthria, truncal, limb and gait ataxia and nystagmus. Symptoms often develop subacutely and progress rapidly over a period of weeks or months to a plateau period that can last for months to years and which often reflects complete loss of Purkinje cells.

Of particular note, PCD symptoms precede the diagnosis of the underlying cancer in the majority of cases, and often present insidiously and progress rapidly for weeks to months to a severely disabled state followed by a variable plateau period that can last for months to years. Therefore, newly developing cerebellar ataxia should always prompt proper diagnostic measures to exclude PCD.

Tumor removal is still the therapeutic mainstay with very early treatment being essential to prevent irreversible neuronal loss. Immunosuppressive or immunomodulatory treatments are often ineffective. There may be a role for high-dose gammaglobulin therapy in the treatment PCD, but due to the rare occurrence of this disease, controlled trials of this therapy may be difficult.

A new model of pathogenesis (lymph node changes are not “benign tumors” that secrete cytokines, but reactive changes due to excessive cytokine release from an as-yet unknown cause) and a new classification system for MCD (based on HHV-8 status) have ensued. CDCN has launched a platform for online discussion among physicians and researchers, developed a global research agenda, and launched a global patient community in partnership with EURODIS and NORD. Current strategic priorities include: 1) establishing a global patient registry, 2) empowering the global patient community to support one another and join the fight against CD, and 3) distributing high-impact research grants.

R. S. Crow, working in Bristol, first described the combination of osteosclerotic myeloma, polyneuropathy and various unusual features (such as pigmentation and clubbing) in two patients aged 54 and 67.

For HHV-8-negative MCD (idiopathic MCD), the following treatments have been used: corticosteroids, rituximab, monoclonal antibodies against IL-6 such as tocilizumab and siltuximab, and the immunomodulator thalidomide.

Prior to 1996 MCD carried a poor prognosis of about 2 years, due to autoimmune hemolytic anemia and non-Hodgkin's lymphoma which may arise as a result of proliferation of infected cells. The timing of diagnosis, with particular attention to the difficulty of determining the cause of B symptoms without a CT scan and lymph node biopsy, may have a significant impact on the prognosis and risk of death. Left untreated, MCD usually gets worse and becomes increasingly difficult and unresponsive to current treatment regimens.

Siltuximab prevents it from binding to the IL-6 receptor, was approved by the U.S. Food and Drug Administration for the treatment of multicentric Castleman disease on April 23, 2014. Preliminary data suggest that treatment siltuximab may achieve tumour and symptomatic response in 34% of patients with MCD.

Other treatments for multicentric Castleman disease include the following:

- Corticosteroids

- Chemotherapy

- Thalidomide

Where an underlying neoplasm is the cause, treatment of this condition is indicated in order to reduce progression of symptoms. For cases without a known cause, treatment involves suppression of the immune system with corticosteroid treatment, intravenous immunoglobulin, immunosuppressive agents like Rituximab, Cellcept, or Imuran or plasmapheresis.

Doege–Potter syndrome (DPS) is a paraneoplastic syndrome in which hypoglycemia is associated with solitary fibrous tumors. The hypoglycemia is the result of the tumors producing insulin-like growth factor 2. The syndrome was first described in 1930, by Karl Walter Doege (1867–1932), a German-American physician and by Roy Pilling Potter (1879–1968), an American radiologist, working independently; the full term "Doege–Potter syndrome" was infrequently used until the publication of a 2000 article using the eponym.

DPS is rare (as of 1976, less than one hundred cases were described), with a malignancy rate of 12–15%. Actual rates of hypoglycemia associated with a fibrous tumor are quite rare (a 1981 study of 360 solitary fibrous tumors of the lungs found that only 4% caused hypoglycemia), and are linked to large tumors with high rates of mitosis. Removal of the tumor will normally resolve the symptoms.

Tumors causing DPS tend to be quite large; in one case a , mass was removed, sufficiently large to cause a collapsed lung. In X-rays, they appear as a single mass with visible, defined borders, appearing at the edges of the lungs or a fissure dividing the lobes of the lungs. Similar hypoglycemic effects have been related to mesenchymal tumors.

Non-steroidal anti-inflammatory drugs (NSAIDs) can give significant relief of the symptoms. Treatment of lung cancer or other causes of hypertrophic osteoarthropathy results in regression of symptoms for some patients.

If LEMS is caused by an underlying cancer, treatment of the cancer usually leads to resolution of the symptoms. Treatment usually consists of chemotherapy, with radiation therapy in those with limited disease.

Some evidence supports the use of intravenous immunoglobulin (IVIG). Immune suppression tends to be less effective than in other autoimmune diseases. Prednisolone (a glucocorticoid or steroid) suppresses the immune response, and the steroid-sparing agent azathioprine may replace it once therapeutic effect has been achieved. IVIG may be used with a degree of effectiveness. Plasma exchange (or plasmapheresis), the removal of plasma proteins such as antibodies and replacement with normal plasma, may provide improvement in acute severe weakness. Again, plasma exchange is less effective than in other related conditions such as myasthenia gravis, and additional immunosuppressive medication is often needed.

Hypertrophic osteoarthropathy is one of many distant effect disorders due to cancer, with lung cancer being the most common cause but also occurring with ovarian or adrenal malignancies. A distant effect disorder, or a paraneoplastic syndrome, affects distant areas and thus is not related to local compression or obstruction effects from the tumor. Other paraneoplastic syndromes include hypercalcemia, SIADH, Cushing's syndrome and a variety of neurological disorders.

The cause is generally either paraneoplastic syndrome or idiopathic. In idiopathic AAG, the body's own immune system damages a receptor in the autonomic ganglia, which is part of a peripheral nerve fibre. If the AAG is paraneoplastic, they have a form of cancer, and their immune system has produced paraneoplastic antibodies in response to the cancer.

Prednisone is an immunosuppressive agent which affects all of the organ systems. Effects on the cellular level include cell activation, replication, differentiation, and mobility. The overall goal is to decrease blistering (inhibition of immediate and delayed hypersensitivity) through decreasing the production of autoantibodies. In order to suppress the production of antibodies, higher doses must be administered. Lesser doses can be prescribed in order to achieve suppression of monocyte function.

Initial treatment involves addressing any existing infections that may have occurred due to the broken state of the skin. Existing wounds are treated with warm compresses, non-adherent (non-stick) dressing, and topical antibiotic ointment. Immunosuppressive agents are administered in attempt to decrease blistering; this is not often effective. The first medication given aiming to heal the wounds are high dose corticosteroids. This is followed by steroid sparing agents which may reduce steroid intake and therefore lessen the side effects. Skin lesions are more likely to respond to this line of treatment than mucosal lesions. However, a high level of caution is advised in patients with a confirmed malignancy, where immunosuppression is vital and dictates treatment options. If the initial therapy fails to control the symptoms of PNP, and the condition of the patient deteriorates, a more aggressive approach may be necessary.

Improvement usually parallels that of the cancer, whether surgical or chemotherapeutic. Generalization of the associated visceral malignancy may worsen the eruption.

In most of the reported cases, the treatment options were very similar. Plasmapheresis alone or in combination with steroids, sometimes also with thymectomy and azathioprine, have been the most frequently used therapeutic approach in treating Morvan’s Syndrome. However, this does not always work, as failed response to steroids and to subsequently added plasmapheresis have been reported. Intravenous immunoglobulin was effective in one case.

In one case, the dramatic response to high-dose oral prednisolone together with pulse methylprednisolone with almost complete disappearance of the symptoms within a short period should induce consideration of corticosteroids.

In another case, the subject was treated with haloperidol (6 mg/day) with some improvement in the psychomotor agitation and hallucinations, but even high doses of carbamazepine given to the subject failed to improve the spontaneous muscle activity. Plasma Exchange (PE) was initiated, and after the third such session, the itching, sweating, mental disturbances, and complex nocturnal behavior improved and these symptoms completely disappeared after the sixth session, with improvement in insomnia and reduced muscle twitching. However, one month after the sixth PE session, there was a progressive worsening of insomnia and diurnal drowsiness, which promptly disappeared after another two PE sessions.

In one case there high dose steroid treatment resulted in a transient improvement, but aggressive immuno-suppressive therapy with cyclophosphamide was necessary to control the disease and result in a dramatic clinical improvement.

In another case, the subject was treated with prednisolone (1 mg/kg body weight) with carbamazepine, propanolol, and amitriptyline. After two weeks, improvement with decreased stiffness and spontaneous muscle activity and improved sleep was observed. After another 7–10 days, the abnormal sleep behavior disappeared completely.

In another case, symptomatic improvement with plasmapheresis, thymectomy, and chronic immunosuppression provide further support for an autoimmune or paraneoplastic basis.

Although thymectomy is believed to be a key element in the proposed treatment, there is a reported case of Morvan’s Syndrome presenting itself post-thymectomy.

Nasopharyngeal carcinoma can be treated by surgery, by chemotherapy, or by radiotherapy. The expression of EBV latent proteins within undifferentiated nasopharyngeal carcinoma can be potentially exploited for immune-based therapies.

Most Cushing's syndrome cases are caused by corticosteroid medications, such as those used for asthma, arthritis, eczema and other inflammatory conditions. Consequently, most patients are effectively treated by carefully tapering off (and eventually stopping) the medication that causes the symptoms.

If an adrenal adenoma is identified, it may be removed by surgery. An ACTH-secreting corticotrophic pituitary adenoma should be removed after diagnosis. Regardless of the adenoma's location, most patients require steroid replacement postoperatively at least in the interim, as long-term suppression of pituitary ACTH and normal adrenal tissue does not recover immediately. Clearly, if both adrenals are removed, replacement with hydrocortisone or prednisolone is imperative.

In those patients not suited for or unwilling to undergo surgery, several drugs have been found to inhibit cortisol synthesis (e.g. ketoconazole, metyrapone) but they are of limited efficacy. Mifepristone is a powerful glucocorticoid type II receptor antagonist and, since it does not interfere with normal cortisol homeostatis type I receptor transmission, may be especially useful for treating the cognitive effects of Cushing's syndrome. However, the medication faces considerable controversy due to its use as an abortifacient. In February 2012, the FDA approved mifepristone to control high blood sugar levels (hyperglycemia) in adult patients who are not candidates for surgery, or who did not respond to prior surgery, with the warning that mifepristone should never be used by pregnant women.

Removal of the adrenals in the absence of a known tumor is occasionally performed to eliminate the production of excess cortisol. In some occasions, this removes negative feedback from a previously occult pituitary adenoma, which starts growing rapidly and produces extreme levels of ACTH, leading to hyperpigmentation. This clinical situation is known as Nelson's syndrome.

Corticosteroids are administered through IV or orally. They cause lymphocytopenia, a condition where white blood cell levels are abnormally low. Corticosteroids cause white blood cell death, lowering their numbers throughout the body. They also cause white blood cells to recirculate away from the area of damage (the retina). This minimizes damage caused by the antibodies produced by the white blood cells. Often, this is treatment is combined with plasmapheresis. Instead of treating the plasma and blood cells, they are replaced with a healthy donor mixture. Patients who respond positively show improved visual fields and an almost complete disappearance of anti-retinal antibodies.

There is no known definitive cure for OMS. However, several drugs have proven to be effective in its treatment.

Some of medication used to treat the symptoms are:

- ACTH has shown improvements in symptoms but can result in an incomplete recovery with residual deficits.

- Corticosteroids (such as "prednisone" or "methylprednisolone") used at high dosages (500 mg - 2 g per day intravenously for a course of 3 to 5 days) can accelerate regression of symptoms. Subsequent very gradual tapering with pills generally follows. Most patients require high doses for months to years before tapering.

- Intravenous Immunoglobulins (IVIg) are often used with varying results.

- Several other immunosuppressive drugs, such as cyclophosphamide and azathioprine, may be helpful in some cases.

- Chemotherapy for neuroblastoma may be effective, although data is contradictory and unconvincing at this point in time.

- Rituximab has been used with encouraging results.

- Other medications are used to treat symptoms without influencing the nature of the disease (symptomatic treatment):

- Trazodone can be useful against irritability and sleep problems

- Additional treatment options include plasmapheresis for severe, steroid-unresponsive relapses.

The National Organization for Rare Disorders (NORD) recommends FLAIR therapy consisting of a three-agent protocol involving front-loaded high-dose ACTH, IVIg, and rituximab that was developed by the National Pediatric Myoclonus Center, and has the best-documented outcomes. Almost all patients (80-90%) show improvement with this treatment and the relapse rate appears to be about 20%.

A more detailed summary of current treatment options can be found at Treatment Options

The following medications should probably be avoided:

- Midazolam - Can cause irritability.

- Melatonin - Is known to stimulate the immune system.

- Also, see for more details