Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome with Purely Osteolytic, Not Osteosclerotic, Lesions Mimicking a Malignant Tumor

Abstract

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare inflammatory disorder with multiple phenotypes. The syndrome has identifiable radiologic characteristics that are the most important when making a diagnosis. X-rays of cases diagnosed with SAPHO syndrome reveal sclerotic lesions or mixed lytic and sclerotic lesions. Pure osteolytic lesions in SAPHO syndrome are rare, and to the best of our knowledge, no study has reported the radiologic change of purely osteolytic lesions to osteosclerotic lesions over time. Herein, we report on the case of a woman experiencing severe left thigh acute pain and having a medical history of palmoplantar pustulosis. Although SAPHO syndrome was suspected because of palmoplantar pustulosis, based on radiologic findings, bone metastasis of a malignant tumor or chronic bacterial osteomyelitis owing to a purely osteolytic lesion was suspected. However, needle biopsy revealed no malignancy and bacterial culture was negative, thus suggesting SAPHO syndrome. Nonsteroidal anti-inflammatory drugs, bisphosphonates, and corticosteroids were administered, which improved the left thigh pain. Furthermore, the radiologic change of osteolytic lesions to osteosclerotic lesions over time was confirmed, leading to the diagnosis of SAPHO syndrome. Our case demonstrates that knowledge of atypical radiologic findings is necessary to diagnose initial SAPHO syndrome.

Synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome with cranial bone involvement: Case report and literature review

“…Imaging findings are also consistent with this process: early radiological findings are osteolytic lesions, and late radiological features are usually osteoproliferative 16 . Kinoshita et al 17 reported a case of left femur involvement in SAPHO syndrome with the radiologic change from osteolytic lesions to osteosclerotic lesions over time confirmed. However, further clinical observation is needed if the sclerosing changes of the dura mater occur in the late stage of SAPHO syndrome due to hypertrophic meningitis caused by cranial bone involvement.…”

“…15 Imaging findings are also consistent with this process: early radiological findings are osteolytic lesions, and late radiological features are usually osteoproliferative. 16 Kinoshita et al 17 reported a case of left femur involvement in SAPHO syndrome with the radiologic change from osteolytic lesions to osteosclerotic lesions over time confirmed.…”

Sternoclavicular Septic Arthritis Caused by Cutibacterium acnes in a Previously Healthy 13-Year-Old Male

“…This may suggest that our patient's infection was slightly more chronic than his symptoms initially suggested. Chronic inflammation of the SC joint can also be seen in conditions such as SAPHO syndrome, and several case reports have described this condition in children 7 . In addition, C. acnes is theorized to trigger an autoimmune chronic inflammatory state in patients with SAPHO syndrome 8 .…”