The bullhead sign: scintigraphic pattern of sternocostoclavicular hyperostosis and pustulotic arthroosteitis

Objective: The purpose of this retrospective study was to examine the value of whole-body nuclear medicine imaging and to evaluate the typical scintigraphic pattern of sternocostoclavicular hyperostosis (SCCH) and/or pustulotic arthroosteitis (PAO). In this entity the correct diagnosis is frequently missed because of uncharacteristic changes in other imaging modalities. Materials and methods: Forty-nine patients (age range 15-65 years old, mean age 36 years) with sternocostoclavicular hyperostosis (SCCH) and/or pustulotic arthroosteitis (PAO) were examined with whole-body scintigraphy and conventional radiography. Result: Forty-three of 49 patients with SCCH/PAO showed a characteristic "bullhead"-like high tracer uptake of the sternocostoclavicular region with the manubrium sterni representing the upper skull and the inflamed sternoclavicular joints corresponding to the horns (= bullhead sign). Scintigraphy revealed additional skeletal manifestations (spondylitis, sacroiliitis, osteitis) in 33 of 49 patients with SCCH and/or PAO. Conclusions: Bone scintigraphy is the imaging modality of choice for the diagnosis of skeletal involvement in PAO. Nuclear medicine reveals unexpected locations and shows the typical pattern of focal hot spots of the spine, sacroiliac joints and/or appendicular skeleton in the large majority of cases in combination with a bullhead-like tracer uptake of the sternocostoclavicular region. The bullhead sign is the typical: and highly specific scintigraphic manifestation of SCCH and PAO in radionuclide bone scans and helps to avoid unnecessary biopsies.