Nasopharyngeal inflammatory pseudotumor showing abducens nerve palsy

Inflammatory pseudotumor (IPT) originated from the nasopharynx is very rare. To the authors' best knowledge, nasopharyngeal pseudotumor accompanied by abducens nerve palsy due to cavernous sinus invasion has not been reported previously. A 28-year-old male presented with abrupt-onset diplopia and right side severe headache. Physical examination revealed a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx. The mass was thought to be a malignant neoplasm such as a carcinoma due to ill-defined, infiltrative tumor extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus on MR images, and hypermetabolic lesion on PET/CT. Histopathology demonstrated inflammatory pseudotumor. The patient was treated with high-dose of oral steroid, and then headache and diplopia was dramatically improved. Although IPT of the nasopharynx is very rare, it is important for otolaryngologists to be aware of this disease process.