Dystrophic calcification

Dystrophic calcification is the deposition of calcium salts in dead or degenerated tissues despite normal blood calcium and phosphorus level.

Dystrophic calcification occurs in-

•      any dead or degenerating tissues in tuberculosis, actinomycosis, actinobacillosis, botryomycosis, old scar.

•      Tissues of metazoan parasites that die in the host tissue, as in trichinosis.

Gross characteristics

1.      Calcium salts are chalky whitish granules.

2.      Honeycombed appearance of tissue after separation of calcium salts.

3.      The tissue is hard to cut and when it is cut, gritty sound occurs.

Microscopic characteristics

1.      Irregular granules of varying degrees in size and shape.

2.      Staining characteristic of calcium salt depends upon the thickness of the salt and the stain used.

•      In H & E stain: purple,

•      In Von Kossa stain: black,

•      In Alizarin stain: orange red.

•      Calcium oxalate reveals no colour because it is neutral substance.

Causes

1.      Presence of dead or dying tissue is the fundamental cause of dystrophic calcification.

2.      The factors that initiate the precipitation of calcium are unknown,

but it has been suggested that

•      local alkalinity,

•      formation of fatty acids or

•      increased level of alkaline phosphatase

in tissue may cause dystrophic calcification.

Significance

1.      Dystrophic calcification is the outcome of necrosis.

2.      It gives mechanical irritation to the surrounding tissues.

3.      It induce no inflammatory reaction.

4.      It may induce pathologic ossification.