17 y/o F with lower extremity weakness, rash, CK=1300, myopathic changes on EMG

SKIN (LOW) 640 x 512		SKIN (HI) 640 x 512
MUSCLE (LOW) 640 x 512		MUSCLE (MEDIUM) 640 x 512

 

Diagnosis?  (SCROLL DOWN)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

DERMATOMYOSITIS

Key histopathologic features:

        Perifascicular atrophy--highly suggestive of dermatomyositis

        Inflammatory infiltrates, consisting of lymphocytes, plasma cells, and macrophages, centered around blood vessels in interfascicular septi and in deep dermal tissue
 

        Damage to and depletion of muscle capillaries is best visualized with epon (resin) sections and electron microscopy.  Capillaries are depleted and endothelial cells show swelling
           IMAGE OF SWOLLEN ENDOTHELIAL CELL and may contain tubular reticular structures