January 26, 2021

Rare tumor disguised as benign

A rare tumor that causes facial weakness was found masquerading as a more common benign facial tumor.

A rare facial nerve tumor that causes progressive facial weakness, including the inability to close eyes and perform normal facial movements, has been detected masquerading as a more common benign facial tumor. 

Nauman Manzoor, MD, and colleagues have found an instance of intraneural perineurioma (INP) that caused progressive facial weakness and radiologically mimicked a schwannoma. Schwannomas are the most common benign tumors of the intratemporal face nerve. 

The research team studied a woman who experienced what they initially believed to be a schwannoma. Suddenly, after 18 years of observation, the patient’s facial weakness progressed rapidly. MRI showed thickening and enhancement of the left intratemporal facial nerve, consistent with the diagnosis of schwannoma. 

Later analysis showed a lack of schwannoma-related markers, with more detailed results supporting the diagnosis of an INP instead. Currently, there is no evidence for malignant transformations of INPs, and this case, reported in JAMA Otolaryngologyhighlights a rare differential in a case of benign lesions involving the facial nerve.