[The "bull horn sign"--scintigraphic pattern in sternocostoclavicular hyperostosis and pustular arthro-osteitis]

27 patients with sternocostoclavicular hyperostosis (SCC) and/or pustulotic arthroosteitis (PAO) were examined with whole body scintigraphy, conventional radiography, and other imaging modalities, such as CT, MRI. 25 of 27 patients with SCCH showed a characteristic high bullhorn-like uptake of the sternocostoclavicular region with the manubrium sterni representing the skull and the inflamed sternocostoclavicular joints corresponding to the horns (= bullhorn-sign). Scintigraphy revealed additional skeletal manifestations (spondylitis, sacroilitis, osteitis, periostitis) in 19 of the 27 patients with SCCH and/ or PAO. In combination with PPP or psoriasis pustulosa, the typical scintigraphic bullhorn pattern enables the diagnosis of PAO (19 patients) with high confidence. Patients with SCCH but without skin disease at the time of presentation (8 of 27 patients) may develop PPP later and, therefore, it is justified to classify them as incomplete PAO with high risk to develop other skeletal manifestations later in the course of the disease.