A 45 years old man was having problem in the planter flexion of his feet.  The power was weak and the reflexes were normal.  The gastrocnemius and soleus were investigated for muscular vs neuropathic disease.  The muscle biopsy showed the following picture.  The findings are suggestive of which disease?

1. Denervation atrophy
2. Dermatomyositis
3. Inclusion body myositis
4. Myositis due to infectious agents
5. Polymyositis
    

 

 

 

 

Answer:a

Explanation:

(Choice a) In denervation atrophy there is atrophy of a group of muscle fibers i.e. they are reduced in size.

(Choice b) The muscle biopsy in dermatomyositis shows mononuclear cells infilterate in the perimysial tissue.

(Choice c) Inclusion body myositis show cytoplasmic inclusions called “rimmed vacuoles”.

(Choice d) Diffuse inflammatory infilterate is seen in myositis due to infectious agents

(Choice e) The muscle biopsy in Polymyositis shows mononuclear cells infilterate in the endomysial tissue.

Educational Objective:

Muscle biopsy is used to diagnose various diseases of muscle.  Sometimes the grouped atrophy of denervation is very obvious.