Walsh & Hoyt: Other Myopathies

Acute necrotizing myopathy in association with carcinoma is so rare that it is best considered an uncertain entity. Paraneoplastic neuropathies are common, and most patients with subacute proximal weakness and wasting occurring with cancer have neurogenic disease or paraneoplastic myositis. The paucity of clinical, neurophysiologic, and pathologic details in single case reports of paraneoplastic myopathy makes pathophysiologic correlations difficult. Nevertheless, Swash described a patient with bladder carcinoma who developed rapidly progressive, painless, muscular weakness associated with external ophthalmoplegia. The patient died 5 weeks after the onset of symptoms, and postmortem examination of skeletal muscles, including the extraocular muscles, showed variable fiber size, endomysial edema, and scattered fibers undergoing hyaline necrosis or phagocytosis; however, vacuolar changes appeared to predominate over necrosis. Although the patient also had evidence of an acute carcinomatous neuropathy at autopsy, with few motor end-plates being identified even in the extraocular muscles, it was thought that the acute neuropathy supervened during the last 3 weeks of the patients life and that the initial paralysis, including the ophthalmoplegia, was probably caused by the necrotizing myopathy.