Magnetic resonance imaging of syringocystadenoma papilliferum of the external auditory canal.

Syringocystadenoma papilliferum (SCAP) usually occurs on the face or the scalp and is very rare in the external auditory canal (EAC). There has been no information on magnetic resonance (MR) imaging of this tumor irrespective of its site. We report here a case of 57-year-old man having this tumor, which was surgically removed and its histopathology was confirmed. MR imaging demonstrated a lobulated 4-cm mass with clearly defined margins in the EAC. Although the tumor was bulky, these MR findings were different from the malignancies. The mass lesion showed intermediate signal intensity both on T1- and T2-weighted MR images and showed slight enhancement on gadolinium-enhanced T1-weighted images. Signal intensities on T2-weighted images of this tumor were low compared to those of pleomorphic adenoma. All ceruminous gland tumors including SCAP are thought to be potentially malignant; therefore, pre-operative biopsy should not be performed. Even though incisional biopsy is sometimes needed as in our case, the current MR features would be helpful for differential diagnosis of this rare condition and assessing the extension of the tumor.