Bone Scan and SPECT/CT Scan in SAPHO Syndrome

Abstract

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare clinical entity involving musculoskeletal and dermatologic systems. Its main features are prominent inflammatory cutaneous and articular manifestations. Anterior chest wall pain, more commonly at sternoclavicular and sternocostal joints, along with palmoplantar pustulosis and acne can point to this uncommon syndrome. Here, we report a case of a 15-year-old female, who presented with swelling at the anterior chest wall, was referred for the bone scan. Bone scintigraphy and single-photon emission computed tomography (SPECT/CT) detected classical “bull-head” sign, and further physical examination, for skin lesions, confirmed the diagnosis.

A 15-year-old female with a history of pain and swelling in the anterior chest wall, centered at bilateral clavicular regions for 8 months, was referred for bone scintigraphy. A complete blood count, erythrocyte sedimentation rate, and serum C-reactive protein were normal. Whole-body bone scan anterior and posterior images [Figure 1a and b] revealed increased tracer uptake in bilateral sternoclavicular joints (left >> right), left clavicle, sternum, bilateral first sternocostal joints and bilateral sacro-iliac joints. The images show intense tracer uptake at the sternoclavicular joints and sternum, which represent a “bullhead” sign, described in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. It was first described by Freyschmidt and Sternberg.[1] Single-photon emission computed tomography–computed tomography (SPECT-CT) scan was also done for further evaluation. Computed tomographic three-dimensional reconstruction [Figure 1c] of the bones of the anterior chest wall showed hyperostosis of the left clavicle. Fused SPECT-CT coronal and axial images [Figure 1d–g] showed expansile osteolytic, sclerotic destructive lesions in bilateral clavicles and chondral ends of bilateral first ribs (left >> right). The characteristic “bullhead” sign raises suspicion of SAPHO syndrome. On physical examination, rashes were detected on the palms and soles of the patient. The diagnosis of SAPHO syndrome was considered based on the presence of one of the diagnostic criteria formulated by Benhamou et al.[2]

Figure 1.

Whole-body bone scan anterior and posterior images (a and b) show increased tracer uptake in bilateral sternoclavicular joints (left >> right), left clavicle, sternum, bilateral first sternocostal joints, and bilateral sacroiliac joints. Computed tomographic three-dimensional reconstruction (c) of the bones of the anterior chest wall shows hyperostosis of the left clavicle. Fused single-photon emission computed tomography-computed tomography coronal and axial images (d-g) show expansile osteolytic, sclerotic destructive lesions in bilateral clavicles and chondral ends of bilateral first ribs (left >> right)

The acronym SAPHO was introduced in 1987.[3] Few case reports of SAPHO syndrome have been discussed in the literature.[4,5,6,7,8] Osteoarticular manifestations involve osteitis, hyperostosis, synovitis, arthropathy, and enthesopathy that present with pain, tenderness, and sometimes swelling over the affected areas and fever. Classical cutaneous lesions seen in SAPHO patients include palmoplantar pustulosis and severe acne.[9] Skin lesions may vary in severity and may precede (in 50% of the cases), follow, or occur simultaneously with the onset of arthritis.[10] The present case highlights the importance of bone scan, SPECT-CT imaging, and physical examination to produce a definite diagnosis of SAPHO.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.