Deposition of calcium pyrophosphate dihydrate crystals (chondrocalcinosis, pseudogout) can occur in the temporomandibular joint.


Clinical features:

(1) The patient is middle-aged or elderly.

(2) The patient may have a history of degenerative arthritis.

(3) The patient may present with:

(3a) arthritis and pain of the temporomandibular joint, which may be bilateral

(3b) a possible tumor of the temporomandibular joint

(3c) a preauricular swelling

(3d) a possible parotid tumor

(3e) a possible tumor of the external ear canal

(3f) dental malocclusion

(3g) trismus


Imaging studies may show:

(1) calcifications or radio-opacities

(2) degenerative change in the TMJ joint (erosion and sclerosis of the fossa, misshapen condyle, etc)

(3) tophaceous mass (infrequent)


Needle aspiration of the mass will show crystals with features of calcium pyrophosphate dihydrate under polarized light (positively birefringent).


The diagnosis can be made if the patient is known to have pseudogout, or if the crystals are identified, or if the diagnosis is considered. Otherwise it may come as a complete surprise.


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