Korean J Otolaryngol-Head Neck Surg.  1998 Jan;41(1):90-95.

Fibrosing Inflammatory Pseudotumors of the Skull Base

• Lee CH
• Sung MW
• Kim KH
• Mo JH
• Kim JY
• Kim WH
• Han MH

Abstract

BACKGROUND AND OBJECTIVES: Mass-forming lesions involving the skull base are challenging to otolaryngologists in many ways. For one, the most important differential diagnosis of a skull base lesion is to rule out the malignant neoplasm, however, nonneoplastic lesions, such as infection or nonspecific inflammatory lesions of the skull base can mimic a malignant process. This study evaluates the clinical manifestations, progression and therapeutic results of fibrosing inflammatory pseudotumors of the skull base.
MATERIALS AND METHODS
We analyzed eight cases of non-neoplastic mass-forming lesions involving the skull base.
RESULTS
In most cases, malignant lesions were initially suspected during diagnostic work-up, but subsequent histologic examinations revealed that these lesions consisted of inflammatory cells and fibrosis without neoplastic cells. The most common manifestations were pain and other various neurologic symptoms related to the involved anatomic sites. All cranial nerve malfunctions except for the olfactory and the spinal accessory nerves were observed in our case studies. No patient in our case studies developed any separate lesion outside of the head and neck region. As these lesions are usually characterized as being hypointense on T2 weighted images unlike the other common skull base malignancy, MRI can offer some clues for preoperative differential diagnosis of pseudotumor from malignancy. After the pathologic diagnosis, most of the patients were treated with extended oral steroid medication, with initial doses of 60-100 mg/day of prednisolone. It was difficult to relate the responsiveness to steroid therapy with the histologic degree of sclerosis/fibrosis or chronicity of the disease in our cases.
CONCLUSION
A fibroinflammatory lesion of the skull base is a rare disease, but, otolaryngologists should be aware of this disease in order to avoid confusion in decision making for the management of skull base lesions.

Keyword

Skull base; Fibrosing inflammatory pseudotumor; MRI; Steroid

MeSH Terms

Accessory Nerve
Cranial Nerves
Decision Making
Diagnosis
Diagnosis, Differential
Fibrosis
Granuloma, Plasma Cell*
Head
Humans
Magnetic Resonance Imaging
Neck
Neurologic Manifestations
Prednisolone
Rare Diseases
Skull Base*
Skull*
Prednisolone