Denervation Atrophy

Epidemiology and Etiology:

· Type 2 fibre atrophy:

o Relatively common

o Inactivity or disuse (disuse atrophy)

§ Limb fracture and casting

o Pyramidal tract degeneration

o Neurodegenerative diseases

o

Common sites:

Gross features:

Histologic features:

• Decrease in cell size
• Angulation of fibres
• Rounded zone of disorganized filaments in the centre of some fibres (target fibre)

Immunophenotype:

Marker:

Sensitivity:

Specificity:

• Type grouping (see normal skeletal muscle for stains)
• Sign of reinervation after denervation
• Group atrophy (when a type group in turn becomes denervated)

Molecular features:

Other features:

References: