Current Therapies for Paraneoplastic Neurologic Syndromes

Neuroendocrine carcinoma of the small intestine diagnosed as a result of paraneoplastic neurological syndrome

Paraneoplastic neurological syndromes, a diverse group of neurological syndromes, are associated with small cell lung, testicular, ovarian, and breast cancers; however, their association with neuroendocrine carcinoma of the small intestine remains unreported. In this report, we present the case of a 78-year-old man diagnosed with neuroendocrine carcinoma of the small intestine and experienced symptoms such as subacute progressive numbness of the extremities and impaired gait. These symptoms were diagnosed as tumor-associated neurological syndrome. The patient had also undergone pyloric gastrectomy for early-stage gastric cancer several years prior to the appearance of the neurological symptoms. Therefore, we could not determine whether the tumor-related neurologic syndrome was owing to gastric cancer or neuroendocrine carcinoma of the small intestine; however, one of these conditions was the cause of the neuropathy. The gait disturbance and numbness relatively improved after surgery for the neuroendocrine carcinoma of the small intestine, suggesting that the neuroendocrine carcinoma of the small intestine likely caused the paraneoplastic neurological syndrome. Collectively, we present a unique report highlighting the putative relationship between small bowel neuroendocrine carcinoma and tumor-associated neurologic syndromes.

CV2/CRMP5-antibody-related Paraneoplastic Neurologic Syndrome Associated with Gastrointestinal Stromal Tumor

Paraneoplastic neurological syndrome (PNS) is a heterogeneous group of neurological disorders caused by immune-mediated inflammatory mechanisms. We herein report a 77-year-old man with CV2/CRMP5-antibody-related PNS associated with a gastrointestinal stromal tumor (GIST). He was admitted for forgetfulness and delusional behavior. His neurological symptoms were subacute, and a whole-body examination revealed a gastric GIST. Serology showed CV2/collapsin response mediator protein (CRMP)-5 antibodies. Partial gastrectomy was performed for the GIST, and the neurological symptoms and serum CV2/CRMP5 antibodies disappeared. No relapse has occurred since the surgery. PNS should be considered in patients with subacute neurological disorders.

Association of Immune-Mediated Cerebellitis With Immune Checkpoint Inhibitor Therapy

Immune-mediated encephalitis related to immune checkpoint inhibitor therapy is a rare but increasingly described condition that can cause significant morbidity. There are several reported cases in the literature but no previously described cases of immune-mediated cerebellitis. We describe a case of acute cerebellitis that developed in a 20-year-old man with primary refractory Hodgkin lymphoma being treated with the immune checkpoint inhibitor nivolumab. After exposure to 3 cycles of nivolumab, the patient had acute onset of headache, ataxia, nausea, and vomiting, with imaging findings of cerebellar edema, early tonsillar herniation, and early hydrocephalus. Immune-mediated cerebellar encephalitis was suspected and high-dose dexamethasone therapy (8 mg every 6 hours) was initiated. Within 4 days of dexamethasone therapy, his symptoms greatly improved with near-complete resolution of symptoms after a 4-week taper. Differential diagnosis of his condition included viral cerebellitis and paraneoplastic cerebellar degeneration. In cerebellar encephalitis suspected to be due to immune checkpoint inhibitor therapy, prompt recognition and early initiation of high-dose corticosteroids is essential for symptom resolution and treatment success, including the prevention of hydrocephalus and tonsillar herniation. Currently, there are no evidence-based guidelines to guide the initial dose, type, or duration of corticosteroids. Further investigation is needed in the pathogenesis and treatment of cerebellar encephalitis related to immune checkpoint inhibitor therapy to effectively treat this rare, disabling condition.

Wilms tumor presenting with Lambert-Eaton myasthenic syndrome

Paraneoplastic syndromes may affect the central and peripheral nervous system of adults and children with cancer. Neurological symptoms may resolve with treatment of the underlying neoplasm. We report the case of a child with Wilms tumor who presented with generalized weakness, fatigue, ptosis, hypokinesis, dysarthria, urinary retention, facial diplegia, ophthalmoplegia, and autonomic dysfunction. Routine electrodiagnostic testing, including repetitive nerve stimulation, was normal. Clinical features and stimulation single-fiber electromyogram were consistent with a neuromuscular junction transmission disorder, likely Lambert-Eaton myasthenic syndrome. The child's neurological status returned to normal with successful treatment of the tumor.

Paraneoplastic neurological syndromes associated with gastric cancer: a case report and review of the literature

Paraneoplastic neurological syndromes (PNS) are associated with small-cell lung cancer, breast and gynecological cancers. We describe a gastric neoplasm presented with neurological symptoms. A 74-year-old male presented with tonic-clonic seizures. Initial investigations were normal; however, brain magnetic resonance imaging showed abnormal signal intensity in the hippocampi. A diagnosis of PNS was suspected. The patient was then diagnosed with a gastric neuroendocrine carcinoma with N-type voltage-gated calcium channel antibodies. The neurological impairments improved after the primary was resected and the patient remains free of cancer and paraneoplastic syndrome. We reviewed 10 cases of PNS associated with gastric cancer and found several characteristics: (1) older men, (2) neuroendocrine component or predominance, (3) oncological outcome for patients with PNS is better than for patients without PNS, and (4) neurological impairment is diagnosed 6 months prior to the diagnosis of gastric malignancy. In conclusion, elderly men with symptoms suggestive of PNS should be investigated for a gastric neuroendocrine malignancy.

Paraneoplastic neurological syndrome in a patient with gastric cancer

Paraneoplastic neurological syndromes (PNSs) are a heterogeneous group of neurological disorders caused by immune-mediated mechanisms. The incidence of PNS is much less than 1% for solid tumors, except for small-cell lung cancer and thymoma. We report a rare case of gastric cancer that presented with primary clinical findings of PNS. The patient was a 63-year-old woman who was admitted for worsening neuropathy. Laboratory and neurological tests excluded a nutritional deficit, diabetes mellitus, and connective tissue disease as causes of her neuropathy. Computed tomography (CT) of the abdomen, positron emission tomography (PET)-CT, and endoscopy of the stomach revealed gastric cancer with lymph node swelling. Distal gastrectomy was performed and pathological and immunohistochemical examinations indicated endocrine cell carcinoma. The gastrectomy stopped the exacerbation of her symptoms and recurrence was not observed, but the neurological disorders were irreversible. This case suggests that early diagnosis of the primary tumor is required to improve the outcome in patients with PNS.

Clinical applications of a peptide-based vaccine for glioblastoma

Glioblastoma multiforme is a malignant, relentless brain cancer with no known cure, and standard therapies leave significant room for the development of better, more effective treatments. Immunotherapy is a promising approach to the treatment of solid tumors that directs the patient's own immune system to destroy tumor cells. The most successful immunologically based cancer therapy to date involves the passive administration of monoclonal antibodies, but significant antitumor responses have also been generated with active vaccination strategies and cell-transfer therapies. This article summarizes the important components of the immune system, discusses the specific difficulty of immunologic privilege in the central nervous system, and reviews treatment approaches that are being attempted, with an emphasis on active immunotherapy using peptide vaccines.

Paraneoplastic syndromes affecting the nervous system

The paraneoplastic neurologic disorders (PND) are a diverse group of diseases characterized by the presence of neurologic dysfunction in the setting of a remote cancer. PND can affect almost any part of the nervous system, and are most commonly associated with lung cancer (small cell) and gynecologic tumors. Laboratory studies have demonstrated that an autoimmune response links the neurologic disorder and the cancer, and established a model whereby the cancer is believed to initiate the syndrome by expressing a protein antigen normally expressed in the nervous system, leading to anti-tumor immune response followed by autoimmune neurologic symptoms. We review the currently known PND and their pathogenesis.