Benign calf amyotrophy: clinicopathologic study of 8 patients.
BACKGROUND
The benign focal amyotrophy disorders have been described since 1959 for the upper limbs and since 1981 for the lower limbs. The clinicopathologic features have pointed to a restricted and self-limiting form of motor neuron disease.


OBJECTIVE
To describe the clinical, electromyographic, and muscle histopathologic features in 8 patients with benign calf amyotrophy.


METHODS
Retrospective review of patient charts, electromyograms, and muscle histopathology.


RESULTS
Eight patients, aged 37 to 88 years, developed insidiously progressive calf muscle weakness and wasting during 1 to 5 years. The gastrocnemius weakness and wasting were bilateral in 4 patients. Initial progression of symptoms was followed by disease stabilization. None had a history of poliomyelitis or family history of neuromuscular disease. Creatine kinase values were mildly elevated in 5 patients. The electromyographic and muscle histopathologic findings were consistent with a chronic neuropathic disorder. Despite the restricted calf muscle involvement clinically, the electromyographic abnormalities suggested more diffuse lower limb involvement. Further studies, including DNA tests and muscle-based protein studies, excluded several types of inherited neuromuscular disorders.


CONCLUSIONS
Benign calf amyotrophy is a variant of the benign focal amyotrophy disorders. The etiology for these disorders is unknown. Studies to exclude other causes of calf amyotrophy and careful follow-up examinations to document disease stabilization are necessary to diagnose this uncommon disorder.
Felice
Kevin J
KJ
Department of Neurology, University of Connecticut Health Center, University of Connecticut School of Medicine, Farmington 06030-1840, USA. felice@nso.uchc.edu
Whitaker
Charles H
CH
Grunnet
Margaret L
ML
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001213:Asian; D003402:Creatine Kinase / Q000097:blood; D000073939:Dysferlin; D016189:Dystrophin / Q000378:metabolism; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D006801:Humans; D007124:Immunoenzyme Techniques; D007866:Leg / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D009124:Muscle Proteins / Q000378:metabolism; D018908:Muscle Weakness / Q000473:pathology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D009133:Muscular Atrophy / Q000473:pathology / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology; D012189:Retrospective Studies; D013116:Spinal Cord / Q000473:pathology; D013131:Spine / Q000473:pathology
C114839:DYSF protein, human; D000073939:Dysferlin; D016189:Dystrophin; D008565:Membrane Proteins; D009124:Muscle Proteins; D003402:Creatine Kinase