The Disappearing Jawbone

A 48-year-old man presented to our department with a 20-year history of acne conglobate and mandibular pain. He initially developed left mandibular pain, followed by atrophy of the mandible. The patient's left mandibular pain resolved within months of a single 30 mg dose of pamidronate, and the atrophy appeared to progress more slowly thereafter. However, pain later developed on the right side. By age 45, he reported left elbow pain. Physical examination revealed mandibular asymmetry, extensive cutaneous and eyelid scarring secondary to acne conglobata (Figure 1A–C), as well as tenderness and swelling of the left elbow with limited extension. Skeletal scintigraphy demonstrated osteitis of the right mandible and alveolar bone, along with increased radionuclide uptake in the sternoxiphoid joint, left sternocostal joint, and left elbow (Figure 1D). Computed tomography confirmed osteolysis of the left mandible (Figure 1E). Magnetic resonance imaging revealed osteomyelitis and hyperostosis of the right mandible (Figure 1F), in addition to synovitis of the left elbow. A diagnosis of SAPHO syndrome (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) was established. Treatment was initiated with weekly methotrexate (15 mg) and biweekly adalimumab (40 mg), resulting in significant symptomatic improvement. SAPHO syndrome represents a clinical spectrum encompassing osteoarticular and dermatological manifestations. Mandibular involvement occurs in only about 2% of cases and is frequently overlooked by general practitioners 1. The cause of mandibular osteolysis in this patient is confusing, as both the underlying disease and bisphosphonate therapy could be responsible. However, the onset of bone atrophy prior to bisphosphonate initiation, along with the osteolytic lesion being localized to the ascending ramus—without typical involvement of the tooth-bearing region seen in bisphosphonate-related osteonecrosis of the jaw—points to SAPHO syndrome as the most likely etiology. Beyond conventional treatments such as NSAIDs, glucocorticosteroids, and conventional DMARDs, biologic agents and targeted DMARDs (e.g., Janus kinase inhibitors) are emerging as effective therapeutic options for SAPHO syndrome 2. This case illustrates the enduring and disfiguring impact of SAPHO syndrome and underscores the importance of early recognition and intervention. X.S. and L.J. managed the patient and drafted the manuscript. K.W. provided the radiographic images. Z.Z. critically reviewed and revised the manuscript. The patient provided written informed consent for publication of this Clinical Picture. The authors have nothing to report. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.