Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is characterized by skin lesions and osteomyelitis. Although the pathogenesis of SAPHO syndrome remains unclear, chronic focal infection may play a role in the development of excessive immune responses.
The patient, a 21-year-old Asian man, was admitted to our department due to jaw swelling and pain. His symptoms began 3 years prior to admission. As he exhibited palmoplantar pustulosis and a bone biopsy revealed aseptic osteomyelitis, he was diagnosed with SAPHO syndrome.1 On admission, painful swelling and bone hypertrophy were observed in his lower jaw and sternoclavicular joint. Severe nodulocystic acne was present on his face and chest (Figure 1A). Bone scintigraphy revealed diffuse uptake in his mandibular area, referred to as “Lincoln sign” because its shape resembles the beard of Abraham Lincoln (Figure 1B). The Lincoln sign on bone scintigraphy, a characteristic feature of Paget disease and hyperparathyroidism,2,3 was previously undescribed in patients with SAPHO syndrome.
(A) Severe nodulocystic acne on face and chest. (B) Bone scintigraphy revealed Lincoln sign, showing diffuse uptake in the mandibular area.
Osteomyelitis in the lower jaw, predominantly unilateral but occasionally bilateral as in this case, develops in 2% to 10% of patients with SAPHO syndrome.4 Additionally, it has been reported that younger onset and lower frequency of skin lesions are demographic characteristics associated with SAPHO syndrome presenting with mandibular osteomyelitis.4 Here we presented a rare case of Lincoln sign in a patient with SAPHO syndrome. Nonsteroidal antiinflammatory drugs and risedronic acid were administrated, and his symptoms gradually improved.
Footnotes
The authors declare no conflicts of interest relevant to this article. This study was approved by the institutional ethics committee, and patient consent was obtained for publication.
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