hematology and oncology
Paraneoplastic Syndromes
Neurologic paraneoplastic syndromes
Several types of peripheral neuropathy are among the neurologic paraneoplastic syndromes. Cerebellar syndromes and other central neurologic paraneoplastic syndromes also occur. Peripheral neuropathyis the most common neurologic paraneoplastic syndrome. It is usually a distal sensorimotor polyneuropathy that causes mild motor weakness, sensory loss, and absent distal reflexes. Subacute sensory neuropathyis a more specific but rare peripheral neuropathy. Dorsal root ganglia degeneration and progressive sensory loss with ataxia but little motor weakness develop; the disorder may be disabling. Anti-Hu, an autoantibody, is found in the serum of some patients with lung cancer. There is no treatment. Guillain-Barré Syndrome (GBS) None Eaton-Lambert syndrome None Subacute cerebellar degenerationcauses progressive bilateral leg and arm ataxia, dysarthria, and sometimes vertigo and diplopia. Neurologic signs may include dementia with or without brain stem signs, ophthalmoplegia, nystagmus, and extensor plantar signs, with prominent dysarthria and arm involvement. Cerebellar degeneration usually progresses over weeks to months, often causing profound disability. Cerebellar degeneration may precede the discovery of the cancer by weeks to years. Anti-Yo, a circulating autoantibody, is found in the serum or cerebrospinal fluid (CSF) of some patients, especially women with breast or ovarian cancer. MRI or CT may show cerebellar atrophy, especially late in the disease. Characteristic pathologic changes include widespread loss of Purkinje cells and lymphocytic cuffing of deep blood vessels. CSF occasionally has mild lymphocytic pleocytosis. Treatment is nonspecific, but some improvement may follow successful cancer therapy. Opsoclonus(spontaneous chaotic eye movements) is a rare cerebellar syndrome that may accompany childhood neuroblastoma. It is associated with cerebellar ataxia and myoclonus of the trunk and extremities. Anti-Ri, a circulating autoantibody, may be present. The syndrome often responds to corticosteroids and treatment of the cancer. Subacute motor neuronopathyis a rare disorder causing painless lower motor neuron weakness of upper and lower extremities, usually in patients with Hodgkin lymphoma or other lymphomas. Anterior horn cells degenerate. Spontaneous improvement usually occurs. Subacute necrotizing myelopathyis a rare syndrome in which rapid ascending sensory and motor loss occurs in gray and white matter of the spinal cord, leading to paraplegia. MRI helps rule out epidural compression from metastatic tumor—a much more common cause of rapidly progressive spinal cord dysfunction in patients with cancer. MRI may show necrosis in the spinal cord. Encephalitismay occur as a paraneoplastic syndrome, taking several different forms, depending on the area of the brain involved. Global encephalitis has been proposed to explain the encephalopathy that occurs most commonly in small cell lung cancer. Limbic encephalitis is characterized by anxiety and depression, leading to memory loss, agitation, confusion, hallucinations, and behavioral abnormalities. Anti-Hu antibodies, directed against RNA binding proteins, may be present in the serum and spinal fluid. MRI may disclose areas of increased contrast uptake and edema. 