2025 Proffered Presentations
S324: TEMPORO-MANDIBULAR JOINT PSEUDOGOUT AS A DIFFERENTIAL DIAGNOSIS OF SKULL BASE TUMOR : A SYSTEMIC REVIEW
Julie Rosuel, MD; Arnaud Damecourt; Julien Boetto, MD, PhD; CHU Montpellier
Pseudogout (PG) is a form of arthritis due to deposition of calcium pyrophosphate dihydrate in the joints. It generally affects knees, hands, wrists, shoulders, hips, elbows and ankles. In very rare cases, pseudogout can affect the temporomandibular joint (TMJ) and mimic a tumor of the middle skull base. We aim to provide a systematic review of all cases of PG affecting the temporomandibular joint, in order to describe their demographic and radiologic characteristics, as well as the treatment modalities.
A systematic Medline search was made in accordance to the PRISMA guidelines. We identified 89 cases of TMJ pseudogout published from 1976 to 2024, including a new case that we describe. Median age at diagnosis was 60 years old (IQR 53-72). 64% of cases were described in female. Median time from symptoms onset to diagnosis was very long (52 months). Most frequent clinical manifestations were pain (67%) and swelling (66%) of the temporal region, limitation of joint movement (50%) and hearing loss (18%). Radiological aspect was unspecific (heterogeneous mass with calcifications involving the TMJ and eroding the bony adjacent structures on the computed tomography scan, and heterogeneous mass with inconstant signal intensity and variable contrast enhancement on the MRI scan). Middle skull base was radiologically involved in more than 50% of all cases. Suspected diagnoses based on radiological imaging were osteochondroma, chondrosarcoma, fibrous dysplasia, or synovial chondromatosis, or other osseous/cartilaginous primary tumors. Interestingly, PG diagnosis was never suspected in cases extending beyond the TMJ. Pre-operative biopsy was made in 39 cases out of the 89 (40%), and enabled the diagnosis in 30 cases. Surgical resection was proposed as first line treatment in 62 cases (70%). In cases with PG diagnosis confirmed by biopsy, 55% of patients needed surgical resection to release their symptoms after failure of medical treatment. Interestingly, patients with involvement of the skull base had surgical resection in all cases. With a 20.6 months median follow-up in published cases, 3 patients showed local mass recurrence despite surgical resection and needed a new surgery.
Pseudogout is a rare differential diagnosis of primitive osseous or cartilaginous tumors involving the TMJ and the middle skull base. It must be suspected in patients with progressive painful swelling of the TMJ when radiological assessment shows a heterogeneous partially calcified mass involving the TMJ and extending into the middle cranial fossa or the petrous bone. Needle biopsy generally confirms the diagnosis. A medical treatment can be proposed for small size lesions, but surgical resection is generally needed in order to release the symptoms. Even if carcinologic “en-bloc” resection is not recommended, recurrence can occur and follow-up of these patients is thus mandatory, as well as control of the risk factors of PG (Hypomagnesemia, hyperparathyroidism, hemochromatosis, osteopenia and chronic kidney disease).