SAPHO syndrome of the temporomandibular joint associated with trismus: a case report and review of the literature.

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a disorder characterized by pustular skin lesions and osteoarticular lesions. Mandibular involvement occurs in approximately 10% of the cases, and is often seen as recurrent mandibular osteitis with bone sclerosis, mainly involving the body of the mandible in the head and neck region. Middle cranial base with temporomandibular joint (TMJ) involvement in SAPHO syndrome can be diagnostically challenging because of its rarity. Herein, we present a case of a 37-year-old man who suffered from trismus and dull pain in the left TMJ region. The initial panoramic image revealed spotty osteolysis around the left condylar head. Computed tomography (CT) images showed an osteosclerotic change in the middle cranial base including the TMJ. Magnetic resonance images showed a cortical bone change in the left TMJ without anterior disk displacement, with spotty low signal intensity in the left condyle bone marrow on T2- weighted images. Our initial diagnosis was osteomyelitis of the middle cranial base including the TMJ region. However, antimicrobial therapy, training for TMJ opening, and a surgical procedure were not effective. A detailed medical interview, careful check for skin lesions, and further imaging examinations including bone scintigraphy and chest CT led to the diagnosis of SAPHO syndrome. The possibility of SAPHO syndrome should be considered in patients suspected of osteomyelitis of the middle cranial base including the TMJ with unknown etiology.