A Case of Neutrophilic Myositis

ABSTRACT

Neutrophilic myositis is a very rare disease histologically characterized by neutrophil infiltration of muscle tissues. We report a case of a 47-year-old man who presented with acute onset of severe swelling and pain on his left shoulder with high fever. He was initially suspected of having cellulitis, but intravenous antibiotics did not improve his symptoms. Similar swelling and pain then developed on both calves. Investigations with magnetic resonance imaging of the lower legs and muscle biopsy led to a diagnosis of neutrophilic myositis. High dose glucocorticoid dramatically improved his symptoms within days. Clinicians need to be aware of this rare disease as a cause of acute febrile myositis mimicking infection.