Diagnosis of skull base lesions: The role of CT guided biopsy

Accurate histologie diagnosis is important for treatment planning of skull base lesions. However, obtaining tissue diagnosis of lesions in or around the skull base can be difficult. Extensive surgery is often required for tissue biopsy with the potential for debilitating complications. This paper describes the usefulness of CT guided biopsy of lesions located at various sites in the skull base for establishing histologie diagnosis. CT guided biopsies of lesions in and around the skull base (pterygopalatine region, greater wing of the sphenoid, parapharyngeal space, infratemporal fossa) were performed in 5 patients who otherwise would have required complicated open surgical approaches. Biopsies were obtained using 18 to 22 gauge needles via one of two approaches - through the coronoid notch or transorally. Accurate diagnosis (metastatic prostate cancer, squamous cell carcinoma, and pleomorphic adenoma) was made in all of the patients, which ultimately defined treatment. CT guided biopsy is a simple and valuable tool for establishing accurate diagnosis of masses that are located in regions that are not readily accessible for surgical biopsy, such as pterygopalatine region, infratemporal and temporal fossa, parapharyngeal space, and clivai region. Furthermore, it can be used to perform repeat biopsies to monitor response to cancer therapy. The techniques and guidelines will be discussed in detail.