Calcium pyrophosphate deposition disease of the temporomandibular joint invading the middle cranial fossa: Two case reports

BACKGROUND: Pseudogout is a benign joint lesion caused by the deposition of calcium pyro-phosphate dihydrate crystals, but it is invasive. Pseudogout of the temporo-mandibular joint (TMJ) is uncommon, and it rarely invades the skull base or penetrates into the middle cranial fossa. The disease has no characteristic clinical manifestations and is easily misdiagnosed. CASE SUMMARY: We present two cases of tophaceous pseudogout of the TMJ invading the middle cranial fossa. A 46-year-old woman with a history of diabetes for more than 10 years was admitted to the hospital due to swelling and pain in the right temporal region. Another patient, a 52-year-old man with a mass in the left TMJ for 6 years, was admitted to the hospital. Maxillofacial imaging showed a calcified mass and severe bone destruction of the skull base in the TMJ area. Both patients underwent excision of the lesion. The lesion was pathologically diagnosed as tophaceous pseudogout. The symptoms in these patients were relieved after surgery. CONCLUSION: Tophaceous pseudogout should be considered when there is a calcified mass in the TMJ with or without bone destruction. A pathological examination is the gold standard for diagnosing this disease. Surgical treatment is currently the recommended treatment, and the prognosis is good after surgery.