Calcifying tendinitis with osseous involvement : A diagnostic challenge

Abstract

The goal of this article is the radiological visualization of the often very difficult pathoanatomical changes associated with calcifying tendinitis, which in rare cases may erode and ultimately invade the bone. We investigated the diagnostic reliability of radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) in 11patients with calcifying tendinitis. Eight lesions were located in the upper (4supraspinatus tendon, 2deltoideus tendon, 1pectoralis tendon, 1biceps tendon) and 3in the lower extremity (2gluteus tendon, 1adductor magnus tendon). The average age was 58years (8women, 3men). Calcifying tendinitis is the consequence of overuse of an enthesis with consecutive necrosis and calcification. However, in rare cases, erosion of the underlying bone with bone invasion, which is associated with sudden escalation of long-term pain, is observed. The detection of the pathoanatomical changes using MRI is problematic because with this method calcifications and ossifications are only indirectly visualized and, thus, can only be interpreted with uncertainty. The method of choice is CT, which can be used to demonstrate the three key elements of calcifying tendinitis, i.e., the calcified/ossified part of the tendon in the insertion area, adefect in the cortex, and calcification in the medullary space.