To investigate the characterization of adenoid cystic carcinoma (ACC) in major salivary glandby conventional and contrast-enhanced ultrasound (CEUS).

The conventional and contrast-enhanced ultrasound images of 17 ACC in major salivary gland with pathological confirmation were retrospectively reviewed.

12 (70.6%) cases in 17 were found in submandibular, while 5 cases (29.4%) were in parotid. All the patients complained a mass, 52.9% had cheek pain, and 17.6% had hadfacial nerve or lingual nerve paralysis; these symptoms had been present from 3 to 240 months (mean duration was 42.9±62.1 months). 14 cases (82.4%) were primary focuses, and 3 cases (17.6%) were recurrences with recurrence time from 36 to 132 months (mean recurrence time was 70.7±43.2 months). All lesions were hypoechoic with irregular shape, and only 17.6% had a homogeneous echotexture, 64.7% heterogeneous. 64.7% of all tumors were well-defined. On CDFI, blood flow signal hadn?t detected in 23.5% patients, and 64.7% hadintermediate (+ and + + ) grades of vascularity. Only 11.8% had the highest grade of vascularity (+ + + ). The CEUS images of ACC in major salivary showed slow fill-in, centripetal, higher enhancement, inhomogeneous enhancement, poorly defined margins and after enhancing the size unchanged. No enhancement orlow enhancement area were common in the AC. Facial nerve invasion can be seen in all cases, including 3 cases (17.6%) of lingual nerve invasion, 4 cases (23.5%) of blood vessel invasion; 4 cases (23.5%) of striated muscle infiltration; 1 case with mandibular involvement; 1 case (5.9%) with cervical lymph node metastasis. 94.1% of ACC in major salivary gland were cribriform patterns, and 5.9% were solid patterns.

ACC in major salivary gland are more likely to happen in the submandibular gland, which has especially high tendency of facial nerve invasion and cheek pain. Conventional Ultrasound and CEUS imaging characteristics can be used to differentiate ACC from other tumors in major salivary gland, which would help clinicians to diagnose. The clinical course is characterized by very late recurrences; consequently, longer following-up with ultrasound is proposed.