Abstract

57-year-old right handed female, full time dental hygienist with minimal past medical history and family history of Kennedy’s disease (brother) presented with proximal upper extremity weakness and non-radicular pain in her neck and shoulders. Later lower extremities and axial weakness also have developed. During a few years her weakness has progressed to the point
that she could no longer turn over in bed.

Physical examination revealed severe scapular winging bilaterally and weakness of deltoids, biceps, triceps and shoulder girdle muscles as well as small muscles of hands and muscles of thigh. MRI scan (upper arm myositis protocol) revealed intramuscular edema in several upper extremity muscles including biceps, triceps, brachialis and trapezius muscles, suggestive of active myositis. EMG/NCS studies demonstrated myopathic changes, but without clear inflammatory or myonecrotic features. Also, CK level has been normal (77 U/L) and no specific myopathic antibodies have been discovered. Instead, there was mild kappa restricted plasmacytosis (10%), consistent with MGUS. Dystrophy related molecular genetic testing came back negative. Biopsy of left biceps is performed.

What is/are?

1 : Possible differential diagnosis after reviewing H&E and Gomori trichrome stains?
2 : Ultrastructural diagnosis after reviewing electron microscopy?
3 : Role of molecular genetic testing in this type of muscle disorders?
4 : How treatable this condition is and which interventions might be beneficial?