Tenosynovial giant cell tumor in the elbow of a child with the sole symptom of extension disturbance

Abstract

Abstract Introduction Tenosynovial giant cell tumor (TSGCT) is a benign but aggressive lesion, primarily involving large joints. The elbow joint is rarely affected by TSGCT. The common symptoms of the affected joint are pain and swelling. Extension disturbance as a symptom can occur but is rare as the sole symptom. Case Presentation A 13-year-old boy with TSGCT in the elbow had suffered from an extension disturbance over several months. Changes on the plain radiograph were subtle, but expansion of the cubital fossa was recognized retrospectively. Computed tomography (CT) showed an osteolytic lesion in the cubital fossa. Magnetic resonance imaging (MRI) revealed an osseous lesion with low- to intermediate-signal intensity on T1-weighted and high-signal intensity on T2-weighted images. The preoperative diagnosis was a bone tumor, possibly a chondroblastoma considering the age of the patient. In surgery, the osseous lesion as well as a small synovia-like nodule at the tip of the olecranon was diagnosed as TSGCT. The extraosseous lesion with low- to intermediate-signal intensity on T1- and T2-weighted images was the cause of the extension disturbance and resolved after resection. Conclusions A different signal intensity between osseous and synovial-like lesions, in addition to osteolysis with subtle changes on the plain radiograph, made preoperative diagnosis of TSGCT difficult. The synovial-like nodule caused the extension disturbance. The diagnosis of TSGCT in the current Case with the sole symptom of extension disturbance and atypical imaging findings was difficult, and the case may be instructive to others.