Tuberculosis of the parotid lymph nodes: clinical and imaging features

OBJECTIVES: To characterize clinical, computed tomography (CT) and magnetic resonance imaging (MRI) features of tuberculosis (TB) of the parotid nodes. MATERIALS AND METHODS: CT (n=21) and MR (n=7) images, and clinical data from 25 patients with TB of the parotid nodes were retrospectively analyzed by two experienced radiologists who reached consensus. RESULTS: Younger patients (aged <50 years) accounted for 72%. Eighty percent of patients were asymptomatic, and had no history of TB exposure. According to clinical and imaging findings, 64% and 60% patients were misdiagnosed as having tumors, respectively. A total of 43 lesions were identified. Thirty-eight (88.4%) lesions involved the superficial lobe. Fourteen (56%) cases had multiple lesions. There were four types of changes in the parotid fascia: local thickening (40%, n=10); local rupture with thickened adjacent skin (28%, n=7); focal bulge (20%, n=5); and no changes (12%, n=3). Cervical lymphadenopathy was seen in 14 out of 25 cases (56%). The lesions were contrast-enhanced in four patterns on CT images: homogeneous enhancement (37.1%, n=13), irregular cyst-like enhancement (37.1%, n=13), thick-walled ring enhancement (14.2%, n=5), and garland-like enhancement (11.4%, n=4). On MRI, the signal intensity of lesions was isointense on T1-weighted image, hyperintense on T2-weighted image, markedly hyperintense on diffusion-weighted imaging, and low on the apparent diffusion coefficient map. The surrounding parotid parenchymal edema was identified clearly on coronal MR images. CONCLUSION: TB of the parotid nodes tend to simulate tumors clinically and radiologically. Their preferential sites are the superficial lobe. In young patients with positive purified protein derivative skin test and lesions accompanied by cervical lymphadenopathy, changes in the parotid fascia and parotid parenchymal edema adjacent to the lesions on CT and MRI may be helpful in the diagnosis and to facilitate differential diagnosis.