Overview

Inflammatory pseudotumor of the skull base is a lesion near on in the lower parts of the skull.  When viewed with a microscope the lesion consists of multiple types of immune system cells and other cells, which together represent inflammation.  Pseudo (like a) tumor refers to symptoms, signs and radiology appearance similar to cancer without microscopic findings to suggest that the lesion is a malignant cancer.  Inflammatory pseudotumor can occur in many locations in the body other than the skull base, with the most common being the lung and eye socket.   

Symptoms

Symptoms experienced by the patient and signs observed by health care providers depend on where the lesion is located. In one study the most common symptoms was pain in almost 60% of cases. Vision or hearing loss were experienced in approximately 25% of patients¹.

Diagnosis

Inflammatory pseudotumor is suspected when neuro-imaging such as magnetic resonance imaging (MRI) or computed tomography (CT) done for evaluation of a patient’s symptoms shows a lesion in the area their symptoms are coming from.  The MRI and CT findings are usually inconclusive and definitive diagnosis is based on biopsy, which involves removing of a piece or the entire lesion using a needle or surgery and examining it under the microscope.  Some microscopic findings can help classify the specific type of inflammatory pseudotumor.

Treatment

Treatment depends on the location of the lesion and can include surgery for partial or complete removal and/or medications to suppress the immune system such as steroids to shrink the lesion.  Radiation therapy is sometimes used.

References:

1. Alyono JC, Shi Y, Berry GJ, Rceht LD, Harsh GR et al. Inflammatory Pseudotumors of the Skull Base: Meta-Analysis. Otol Neurotol 2015; 36: 1432-1438