Pleomorphic adenoma of parotid gland: MR imaging findings

Objective: To evaluate the diagnostic value of MR imaging and conventional contrast -enhanced MR imaging appearance in pleomorphic adenoma (PA) of the parotid gland.

Methods: We retrospectively reviewed pre- and post-contrast MR images of pleomorphic adenoma with pathologic correlation in 17 cases (6 men and 11 women; median age, 50 years; range, 27-70 years) collected between 2005 and 2011 from our pathologic and radiologic database.

Results: All of the tumors showed well-defined margins, and 12 patients with lobulations. The tumors in 16 patients had capsules. The average maximal diameter was 2.6cm (ranged from 1.0 to 6.3cm). Cystic changes were seen in 6 cases and calcification in 2 cases. On T1-weighted images (T1WI), all tumors showed homogeneously SI equal or lower to normal muscle. On fat-suppressed T2-weighted images (T2WI), all of them showed marked higher SI. On gadolinium-enhanced T1WI, all tumors demonstrated marked enhancement. The tumor showed homogenous enhancement in 4 cases and inhomogeneous in the remaining 13 cases. The enhancement pattern showed low wash-in.

Conclusions: PA of the parotid gland tends to be an isolated and well-defined mass with lobulations, capsules and cystic and/or calcification changes on MR imaging. PA of the parotid gland had characteristics in delayed enhancement patterns.