Vincristine-induced Vacuolar myopathy

Previously unreported vacuolar changes were seen in skeletal muscles of male Sprague-Dawley rats given LD 50 doses of vincristine sulfate. Morphologic changes involving 10.20% of the muscle fibers were seen starting 4 days after vincristine administration and consist of the following: appearance of one or more centrally located vacuoles, atrophy of muscle fibers and sarcolemmal proliferation. By day 8, muscle involvement approached 100% in most sections and consisted of extensive vacuolization plus sarcolemmal proliferation without round-cell infiltrationThat myopathy may be caused by vincristine administration has been proved in rodents.(Summary)

A Case of Incontinentia Pigmenti with Destructive Encephalopathy

Becker muscular dystrophy is a X-linked recessive disease with the affected gene at locus Xp21, characterized by progressive muscular weakness. Without the definite family history, it has been known that the diagnosis of this disease is almost impossible on clinical grounds alone. We reviewed the muscle pathology of two casses of genetically confirmed Becker muscular dystrophy to know the diagnositc significances of this study. The first case, a 20 year old man, is the classical one with definite family history of X-linked recessive heredity. The muscle pathology of the biceps showed dystrophic muscular changes, including increased internal nuclei, marked variation of fiber sizes and mild endomysial fibrosis. The dystrophin stain of the muscle was also confirmative for the diagnosis. The second case was a 32 year old man who has been biopsied his left vastus lateralis 5 years before this genetic diagnosis. This case is a sporadic one without the family history. The diagnosis at the time of muscle biopsy was limb-girdle muscular dystorphy or inclusion body myositis because of the typical rimmed vacuoles and marked variation of fiber sizes. The dystophin stain was not available at that time. Our conclusion is that the molecular genetic study and/or dystrophin protein test of muscle biopsy should be done in every clinically suspected patient, including limb-girdle muscular dystorphy, inclusion body myositis or rimmed vacuolar myopathies.

Glycogen Storage Disease Type II: A Case Report

Glycogen Storage Disease Type II is caused by the deficiency of acid maltase resulting in lysosomal accumulation of glycogen. There are two major clinical syndromes, a severe generalized and invariable fatal disease of infancy, and a myopathy starting in juvenile or adult life. The clinical and laboratory findings of a patient with Glycogen Storage Disease Type II are presented. The patient, a 17-year-old male, experienced slowly progressive weakness of muscle of the pelvis shoulder girdles and trunk. Muscle biopsy showed vacuolar myopathy and electromyograph showed features of myopathy with fibrillation potentials, positive sharp waves, myotonic discharges, without clinical myotonia at rest, and polyphasic potentials on volition. Clinical features, histopathologic and electrophysiologic findings of this disease and differential diagnosis were reviewed.