Case Report: A Patient Presents with Rare, Fulminant SAPHO Syndrome

Upon follow-up in the rheumatology clinic, he showed only modest improvement on methotrexate and prednisone. A nuclear bone scan was performed, revealing hypermetabolic lesions of his cervical, thoracic and lumbar spine, his sterno-manubrio-clavicular joints, his left shoulder and his right knee. The lesion of the sterno­clavicular site provided the bull’s head sign (see Figure 3), and the diagnosis of SAPHO syndrome was confirmed given the constellation of findings.

Figure 3. A whole-body bone scintigraphy revealed the pathognomonic finding of the bull’s head enhancement correlating with osteitis of the sterno-manubrio-clavicular articulations bilaterally (see red arrow). You can also see the enhancement in the spine, both knees, left shoulder and right maxillary/mandibular regions.

Infliximab therapy was initiated, which led to significant improvements in syno­vitis, stiffness and dermatitis. Both prednisone and methotrexate therapy were later tapered off, and he continues to do well on anti-tumor necrosis factor (TNF) therapy.

He was referred to physical therapy and now ambulates independently. He has regained his appetite, and his weight has returned to normal.

Discussion

SAPHO syndrome is a rare, heterogeneous, inflammatory disease affecting osteoarticular and cutaneous tissues.¹ It has many previous names, a few of which include bilateral clavicular osteomyelitis with palmoplantar pustulosis, subacute and chronic clavicular osteo­myelitis, sternoclavicular hyperostosis and chronic recurrent multifocal osteomyelitis (CRMO).²

The classification of SAPHO syndrome is debated because it shares character­istics with spondyloarthritides, sterile dermatoses and osteitis, and auto-inflammatory diseases. The scarce epidemiologic data available seems to link SAPHO to alterations in genes PSTPIP2, PSTPIP1, LPIN2 and NOD2, which are found in several other auto-inflammatory diseases, but no clear causal relationship has been established. A relationship with HLA-B27 positivity also remains controversial because literature both supports and negates an HLA-B27 association with SAPHO.^1,2

Clinical findings include enthesitis, sacroiliitis, peripheral arthritis and axial hyperostosis, mimicking spondyloarthropathies. But several features of SAPHO relate to auto-inflammatory diseases, such as histological infiltrates dominated by neutrophils resembling sterile, neutrophilic dermatoses.^1,2 Overall, SAPHO’s poor association with HLA-B27 seems to argue against SAPHO being a member of the spondyloarthropathies.^3,4

Women are more commonly affected by SAPHO than men in the small cohorts providing epidemiologic data, and the disease seems to manifest in the fourth to fifth decade of life, although it can present at any age.^3-5 Our patient highlights a rare presentation because the individual was a man in his 20s.

Consistent clinical findings of SAPHO include the insidious onset of inflammatory polyarthritis, sterno-manubrio-clavicular joint arthritis and the presentation of cutaneous disease antedating skeletal disease. Up to 55% of sufferers will experience skin symptoms prior to rheumatic symptoms, and peripheral arthritis is more commonly reported than axial disease at any spinal level. The most common dermatoses described are palmar-plantar pustulosis, severe and pustular acne, and hidradenitis suppurativa.