Step I primary hyperparathyroidism & osteitis fibrosa cystica

[MudPhud20XX]

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FA lists OFC as an example of primary hyperparathyroidism, but I can't seem to fine any relation between the two. So the primary hyperparathyroidism leads to OFC? Then what is the mech?

 

[Tajima]

OFC is a consequence of hyperparathyroidism of any cause. Over-secretion of PTH stimulates osteoclasts to lyse bone. Large areas of lysed bone replaced by fibrosis (I do not know the precise mechanism for the fibrosis) produces the hemorrhagic cystic spaces seen in OFC.

 

[tasar1898]

Excessive Osteoclasts--> Eat bone + tiny vessels around --> Hemorrhage into subperiosteal cysts --> Fibrosis by ''healing'' --> looks like brown tumor due to collagen + hemosiderin mixed up