Case ReportsFocal Myositis of Lower Extremity Responsive to Botulinum A ToxinMitrovic, Josko MD, PhD*; Prka, Zeljko MD†; Zic, Rado MD, PhD‡; Marusic, Srecko MD, PhD§; Morovic-Vergles, Jadranka MD, PhD*Author Information *Divisions of Clinical Immunology and Rheumatology and †Hematology, Department of Internal Medicine, ‡Department of Plastic, Reconstructive and Aesthetic Surgery, and §Division of Clinical Pharmacology, Department of Internal Medicine, University Hospital Dubrava, Zagreb, Croatia. The study was supported by a Croatian Ministry of Science, Education and Sports grant (No. 198-1081874-0183) to Prof. Jadranka Morovic-Vergles). Conflicts of Interest and Source of Funding: The authors have no conflicts of interest to declare. Address correspondence and reprint requests to Josko Mitrovic, MD, PhD, Division of Clinical Immunology and Rheumatology, Department of Internal Medicine, University Hospital Dubrava, Zagreb, Croatia; E-mail: firstname.lastname@example.org Clinical Neuropharmacology: March/April 2014 - Volume 37 - Issue 2 - p 55-57 doi: 10.1097/WNF.0000000000000019 Buy Metrics Abstract Focal myositis is a rare, mostly benign disease (pseudotumor) of skeletal muscle, histopathologically characterized by interstitial myositis and tumorous enlargement of a single muscle. The etiology of focal myositis remains unknown; however, localized myopathy has been postulated to be caused by denervation lesions. This case report describes a patient that presented with clinical, laboratory, electromyoneurography, and magnetic resonance imaging features of focal myositis complicated with intervertebral disk protrusion in the lumbosacral spine affected with radicular distress. In most cases, focal myositic lesions show spontaneous regression, relapses are rare, and long-term prognosis is good. There is a wide spectrum of therapeutic options, from no therapy at all through nonsteroidal antirheumatics and glucocorticoids to radiotherapy, surgical excision, and immunosuppressants. In the patient presented, treatment with glucocorticoids, methotrexate, and surgical excision failed to produce satisfactory results. Clinical improvement, pain relief, and reduction in lower leg volume were only achieved by local infiltration of botulinum A toxin. © 2014 by Lippincott Williams & Wilkins.