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Adenoid cystic carcinoma of the head and neck: evaluation with MR imaging and clinical-pathologic correlation in 27 patients.

Twenty-seven adenoid cystic carcinomas (ACCs) of the head and neck in 27 patients were evaluated in a retrospective study based on findings at magnetic resonance (MR) imaging and pathologic and clinical examination. Clinical follow-up was obtained over a mean period of 6.3 years (range of follow-up, 3 months to 17 years); all patients underwent one to seven MR examinations. On T2-weighted images, lesions with low signal intensity corresponded to highly cellular tumors (solid subtype) with a poor prognosis; lesions with high signal intensity corresponded to less cellular tumors (cribriform or tubular subtype) with a better prognosis. MR images were not specific in differentiation of ACCs from other types of tumors; this result underscores the need for biopsy to ensure correct diagnosis. Local, intracranial, osseous, and perineural invasion was depicted, but because of its lack of specificity, MR imaging caused overdiagnosis of tumor extension, particularly perineural spread and bone abnormalities.