Ultrasonographic evaluation of neck masses--sonographic patterns in differential diagnosis.

Ultrasound is a relatively inexpensive, widely available noninvasive method of investigation. Although there is extensive documentation on the use of ultrasound in abdominal lesions, it appears to have been underutilized in the evaluation of neck masses. Ultrasound enables detection of thyroidal and extrathyroidal masses, and definition of their boundaries and their relationship to great vessels. The traditional and exclusive use of ultrasound to separate cystic from solid lesions is outdated. High resolution new-generation real-time machines allow recognition of secondary changes in the structure of basically solid or cystic masses. Infected cystic masses may give the impression of a solid neoplasm. Although partial or total necrosis within a lymph node may simulate a branchial cleft cyst, ultrasonography can in many cases recognize such a "cystic-looking" malignant lymph node and thus prevent a premature biopsy that could transform an initially curable disease into an incurable one.