CT and MR findings of basal cell adenoma of the parotid gland

We report a case of basal cell adenoma in the left parotid gland. A 34-year-old woman presented with a non-tender mass in the left parotid gland. She had first noted it 7- years previously, and it had been gradually increasing in size. The tumor was well-circumscribed with a smooth contour. On noncontrast-enhanced CT, the tumor showed homogeneous soft tissue attenuation. No cystic portion or calcification was seen. The tumor showed homogeneous moderate enhancement on contrast-enhanced CT. Capsule-like ring enhancement was demonstrated. On T1-weighted MR imaging, the tumor was homogeneously hypointense to the surrounding parotid tissue and isointense to muscle. On T2-weighted imaging the tumor was homogeneously hyperintense to muscle but slightly hypointense to the surrounding parotid tissue. On Gd-enhanced T1-weighted imaging, the tumor demonstrated homogeneous moderate enhancement. Capsule-like ring enhancement was also demonstrated. Salivary (technetium-99m-pertechnetate) scintigraphy did not show any uptake in the tumor.