Stepwise Approach to Myopathy in Systemic Disease

Muscle diseases can constitute a large variety of both acquired and hereditary disorders. Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug- and toxin-induced, critical illness myopathy, metabolic, and myopathies with other systemic disorders. Patients with systemic myopathies often present acutely or sub acutely. On the other hand, familial myopathies or dystrophies generally present in a chronic fashion with exceptions of metabolic myopathies where symptoms on occasion can be precipitated acutely. Most of the inflammatory myopathies can have a chance association with malignant lesions; the incidence appears to be specifically increased only in patients with dermatomyositis. In dealing with myopathies associated with systemic illnesses, the focus will be on the acquired causes. Management is beyond the scope of this chapter. Prognosis is based upon the underlying cause and, most of the time, carries a good prognosis. In order to approach a patient with suspected myopathy from systemic disease, a stepwise approach is utilized

Autopsy Proven Peripheral Nervous System Neurolymphomatosis Despite Negative Bilateral Sural Nerve Biopsy

Neurolymphomatosis (NL) refers to a lymphomatous infiltration of peripheral nerves associated with central nervous system or systemic lymphoma, or alternatively, neurodiagnostic evidence of nerve enhancement and/or enlargement beyond the dural sleeve in the setting of primary central nervous system lymphoma or systemic lymphoma. NL is a rare complication of systemic cancer with heterogeneous clinical presentations and an elusive diagnosis. Diagnosis usually requires the demonstration of infiltrating malignant lymphocytes in the peripheral nerve. Infiltration of brain parenchyma, meninges or Virchow–Robin spaces is characteristic of systemic disease at autopsy. We describe a patient presenting with biopsy negative NL affecting exclusively the peripheral nervous system at autopsy