Power Doppler sonography to differentiate tuberculous cervical lymphadenopathy from nasopharyngeal carcinoma

Abstract

Background and purpose: Tuberculous lymphadenitis and metastatic nodes from nasopharyngeal carcinoma are common in Asians and are often indistinguishable clinically. Because their treatment depends on prompt diagnosis, we undertook this study to evaluate if power Doppler sonography could distinguish these two pathologic abnormalities. The intranodal vascular appearances of tuberculous neck nodes are compared with benign reactive neck nodes and metastatic nodes from nasopharyngeal carcinoma.

Methods: The appearances of power Doppler sonograms of 42 tuberculous nodes were compared with 28 metastatic nodes from nasopharyngeal carcinoma and 27 benign reactive nodes. The intranodal distribution of vessels and the intranodal vascular resistance of vessels were compared among these three groups. All examinations were performed by the same sonologist (A.A.), who had more than 3 years' scanning experience, and all data analysis was performed by the same investigator (M.Y.).

Results: The intranodal vascular distribution in tuberculous nodes was varied and simulated both benign and malignant disease. Avascularity of nodes and displacement of hilar vascularity were frequent in tuberculous nodes. Metastatic nodes from nasopharyngeal carcinoma (resistive index [RI], 0.81+/-0.09; pulsatile index [PI], 1.91+/-0.81) had a higher vascular resistance than did tuberculous nodes (RI, 0.71+/-0.11; PI, 1.34+/-0.55). Tuberculous nodes had a higher vascular resistance than did reactive nodes (RI, 0.66+/-0.09; PI, 1.10+/-0.26).

Conclusion: Avascularity, displaced hilar vessels, and low intranodal vascular resistance are clues that may suggest the tuberculous nature of neck nodes. However, there is overlap of appearance between tuberculous nodes, benign reactive neck nodes, and metastatic nodes. Thus, histologic analysis is often required for a definitive diagnosis.

fig 1.

Power Doppler sonogram of a reactive node showing hilar vascularity.fig 2. Power Doppler sonogram of a malignant node showing capsular vascularity (arrows).fig 3. Power Doppler sonogram of a malignant node showing hilar (arrows) and capsular (arrowheads) vascularity.fig 4. Power Doppler sonogram of a tuberculous node showing displaced hilar vessels. Note the adjacent area of cystic necrosis (arrows).fig 5. Power Doppler sonogram of a tuberculous node showing hilar (arrows) and capsular vascularity (arrowheads).fig 6. Power Doppler sonogram of an avascular tuberculous node. Note areas of cystic necrosis (arrows)