Calcium pyrophosphate dihydrate deposition disease of the temporomandibular joint

A 73-year-old female attended the OMFS department with a history of pain and swelling around the left TMJ region. Clinically, she had reduced mouth opening at 35mm, with normal rotation and lateral deviation of the joints bilaterally. No clicking or crepitus was present on auscultation with a normal occlusion.

Non-contrast CT mastoids with 0.63mm slices. The imaging showed a grossly abnormal left TMJ with remodelling of the condyle head, sclerosis and small osteophytes. There was exuberant mineralisation arising from the joint space with inferior displacement of the left condyle (Figures 1, 2, 3, 4).

The left temporal bone, sphenoid bone and posterior aspect of the left zygomatic arch showed sclerosis and remodelling, as well as small erosions of the mandibular fossa. Smooth periosteal reaction was present on the posterior and lateral margins of the mandibular ramus.

There was swelling of the left pterygoid muscles and minor infiltration of the fat superiorly in the left masticator, parapharyngeal and retroantral spaces. Minor infiltration of the overlying subcutaneous fat with small, likely reactive, lymph nodes was also demonstrated (Figure 5).

Similar, but less marked changes, involving the anterior C1/C2 articulation, were also noted (Figure 6). There were no features suggestive of otitis externa.

CPDD, also known as pseudogout, is a benign rheumatological condition characterised by the accumulation of calcium pyrophosphate dihydrate crystals within joint soft tissues [1]. The condition was first noted by Konn et al. in 1962, where unknown crystalline material was identified in synovial fluid using polarised light microscopy [2].

The condition most commonly affects the knee meniscus and the triangular ligament of the wrist [1], with few cases reported in the temporomandibular joint (TMJ) [3–5], the first being in 1976 by Pritzker et al. [3]. CPDD in the TMJ can present with various clinical manifestations, including pain, swelling, trismus, otalgia and unilateral conductive hearing loss [4,6,7].

Differential diagnoses of this mass included TMJ neoplasms and benign disorders like pigmented villonodular synovitis (PVNS) and synovial chondromatosis, the latter tending to form multiple small, loose calcified bodies. PVNS is primarily a soft tissue lesion, which is peripherally calcified and heterogeneous [8]. The presence of sclerosis, remodelling and smooth periosteal reaction was suggestive of longstanding pathology. This, paired with the intra-articular location of the lesion and lack of chondroid calcifications, made a diagnosis of chondrosarcoma unlikely [9]. The florid mineralisation in the TMJ, along with only mild progression of the lesion on the six-month interval scan and unremarkable blood tests (including white cell count and c-reactive protein), pointed towards a slow-growing inflammatory smooth periosteal reaction. The presence of similar radiographic changes involving C1 and C2 made CPDD the most probable diagnosis.

On discussion and in full acknowledgement that this lesion showed continued growth, a non-surgical management strategy was opted for by the patient. She was referred to rheumatology, who recommended ultrasound-guided corticosteroid injections and colchicine for symptomatic relief; however, the patient felt her symptoms were sufficiently managed with NSAIDs. Microscopic examination can be used to confirm histopathological diagnosis, through open biopsy or excision of the lesion. However, this was not done in this case due to the characteristic radiographic findings and patient’s disinclination to any surgical intervention.

Surgical intervention is warranted in cases where symptoms cannot be managed conservatively, or the patient wishes removal of the lesion [6]. Post-operative risks such as facial nerve damage and joint ankylosis must be considered. Our report shows one of the few documented cases of a conservative medical approach to treatment of TMJ CPDD and highlights the importance of a multidisciplinary approach to the management of rare pathologies.

Written informed patient consent for publication has been obtained.