A comparative study of sonographic and histopathologic findings of tumorous lesions in the parotid gland

Objective. The purpose of this study was to clarify which histopathologic features are visualized on sonograms by comparing sonomorphologic and histopathologic analyses of parotid tumorous lesions on the same plane. Study design. Boundaries, shapes, echo intensity level, distribution of internal echoes, and acoustic enhancement on sonograms of 86 parotid tumorous lesions were retrospectively compared with the histopathologic findings. Results. Unclear boundaries on sonograms corresponded to abundant connective tissue with scattered tumor cell nests. Polygonal shapes on sonograms were revealed to represent tumor cell infiltration on histopathologic sections. The "very hypoechoic" lesions showed significantly high ratio of cystic areas (P < .05) in Warthin tumor. The weakly hyperechoic structures on sonograms were connective tissue, hyaline, and necrotic and keratinized materials. Attenuated posterior echoes were observed in malignant tumors with abundant connective tissue and metaplastic bone formation. Conclusions. To facilitate correct sonographic diagnosis, it is important to ascertain the correlation between sonomorphology and histopathology.