Advancing Preoperative Diagnosis: Case Report and Imaging Analysis of Cervical Spine Tenosynovial Giant Cell Tumor.

BACKGROUND Tenosynovial giant cell tumor (TGCT) is a rare, benign, yet aggressive, lesion, usually involving a bursa or the tendon sheath. Spinal TGCT is quite rare. Its appearance on imaging can mimic other aggressive diseases, including giant cell tumor of bone, metastatic disease, and osteoblastoma, thus posing a diagnostic dilemma. We present a new pathologically confirmed case of localized TGCT arising from the cervical spine facet joint and describe its computed tomography (CT) and magnetic resonance imaging (MRI) findings to enhance awareness and improve the accuracy of preoperative diagnosis. CASE REPORT A 33-year-old man experienced neck pain radiating to the right upper limb for 1 year. The pain had subsequently progressed for 1 month. There was no weakness of the lower limbs or limitation in the cervical spine range of motion (ROM). The cervical CT revealed an osteolytic, expansive destructive lesion concentered in the C5-6 right vertebral lamina and spinal process. MRI demonstrated a lobulated mass with heterogeneous isointensity on T1-weighted images and low signal on T2-weighted images. After contrast enhancement, obvious heterogeneous enhancement was identified, and the time-intensity curve (TIC) was of type II (rapid enhancement with low washout curve). Subsequently, a single-stage combined anterior and posterior en-bloc resection was performed. Stabilization was achieved by C5-6 interbody fusion and posterior internal fixation. Histology and immunohistochemistry were suggestive of localized TGCT. The patient's symptoms improved considerably, and there was no sign of a recurrence during the 2-year follow-up. CONCLUSIONS Our case suggested an osteolytic lesion involving the posterior elements of vertebral facet joints. With low signal intensity on T2-weighted image and type II TIC, the possibility of spinal TGCT should be considered.