Fibrosing Inflammatory Pseudotumor Presenting as Cranial Neuropathy

Imaging features, therapies, and outcomes of fibrosing inflammatory pseudotumor of the nasopharynx: A systematic review

BACKGROUND AND PURPOSE

Fibrosing inflammatory pseudotumor (FIP) of the nasopharynx is a rare nonneoplastic inflammatory lesion that is frequently mistaken for malignancy or infection. It is often misdiagnosed by radiologists as nasopharyngeal carcinoma or lymphoma, resulting in multiple biopsies and delays in diagnosis. The purpose is to understand trends in clinical presentation, imaging findings, treatment modalities, and patient outcomes of nasopharyngeal FIP.

METHODS

MEDLINE and EMBASE databases were queried for articles related to FIP of the nasopharynx. Articles that described cases of FIP involving the nasopharynx were selected. Studies that described inflammatory pseudotumor of the nasopharynx associated with known distinct pathologic entities were excluded.

RESULTS

A total of 19 articles describing 37 patients were included. MRI findings were reported in 32 patients. All cases demonstrated avid gadolinium enhancement. T2-weighted imaging characteristics were described or displayed for 21 patients: 95% demonstrated hypointensity compared to surrounding mucosa. Fluorodeoxyglucose (FDG) PET/CT findings were reported for 6 patients, all demonstrating mild FDG avidity.

CONCLUSIONS

Nasopharyngeal FIP is a histological diagnosis of exclusion that presents with facial pain and, often, cranial neuropathies. Relatively low T2-weighted MRI signal should inform the interpreting neuroradiologist to include FIP as a differential consideration for both the ordering provider and pathologist. Corticosteroid therapy is the most frequently employed therapy and results in partial or complete response in most patients. Radiation therapy and anti-inflammatory medications have also been reported to have potential therapeutic roles.