The purpose of this study was to evaluate the ultrasonographic and CT findings of various diseases that affect the intraparotid lymph node.

The subjects were 32 patients having various diseases involving the intraparotid lymph node. The final confirmed diagnoses were nonspecified benign inflammatory lymphadenopathy (n=20), metastasis (n=5), tuberculous lymphadenitis (n=4), and lymphoma (n=3). For the nonspecified benign inflammatory lymphadenopathy, there were multiple lesions in five patients and bilateral lesions in two patients, and a total of 26 lesions were included in this study. The pathologic proof of the diagnosis was made for 4 of 26 lesions, and by ultrasound follow-up on 22 of 26 lesions. All the patients underwent ultrasound. Color Doppler imaging was also performed in 19 patients and contrast-enhanced CT was also performed in 8 patients. All cases with metastasis, tuberculous lymphadenitis and lymphoma were pathologically confirmed and these patients were all examined with contrast-enhanced CT.

For the nonspecified benign inflammatory lymphadenopathy, all the lesions were seen at the superficial lobe. All twenty six lesions were observed as well-defined ovoid or round hypoechoic nodules with posterior sonic enhancement on ultrasonography. A central echogenic hilum was seen in 12 of 26 inflammatory lymphadenopathies (46%), and a central hilar vascularity was noted in 13 of 19 inflammatory lymphadenopathies (68%) on color Doppler imaging. Contrast-enhanced CT showed well-defined nodules with homogeneous enhancement in most lesions. In 3 lesions, a central low density hilum was seen within a lymph node. In 12 cases with metastasis, tuberculous lymphadenitis and lymphoma, there were multiple lesions in 6 cases. CT revealed intraparotid masses with or without central necrosis and the associated multiple lymph node enlargements in the ipsilateral neck region, and their appearances were similar to that of parotid mass.

Nonspecified benign inflammatory lymphadenopathy involving intraparotid lymph nodes often demonstrated characteristic ultrasonographic findings, including a central echogenic hilum on gray scale US and central hypervascularity on color Doppler ultrasonography. In the metastasic lesions, the tuberculous lymphadenitis and the lymphomas, the multiplicity of lesions and the associated enlarged lymph nodes in the ipsilateral neck region could be helpful in the differential diagnosis.