Introduction: Percutaneous transforamen ovale biopsy(PTC-TFOB) is a possible alternative to open cranial biopsy for lesions of the cavernous sinus(CS) and Meckel’s cave(MC). However, there is only one prior study on PTC-TFOB’s diagnostic utility.

Methods: An electronic search of operative records found 15 PTC-TFOB performed in 13 patients at our institution from 1999–2012. All procedures used CT or fluoroscopic guidance. Records were reviewed for patient and imaging characteristics and diagnostic outcome.

Results: Median age was 61(31–80) years. The most common presenting symptom was trigeminal nerve pain or numbness in 10 patients. Eight patients had left- and 5 had right-sided biopsy. There were no complications. Diagnostic tissue was obtained in 7(54%) patients and included meningioma(n=3), adenocarcinoma(n=1), adenocystic carcinoma(n=1), metastatic melanoma(n=1), and neurosarcoidosis(n=1). One patient had a non-diagnostic biopsy, but a second was diagnostic. All patients had a mass lesion with a median size of 2.4(1.5–3.3)cm that clearly involved the foramen ovale. Six(46%) patients had a non-diagnostic biopsy. All non-diagnostic tissue showed nerve fibers indicating correct location. Four patients had abnormal enhancement of the V3 division of the trigeminal nerve and were ultimately diagnosed with lymphoma(n=2) and metastatic squamous cell carcinoma(n=2) by open cranial(n=2), facial nerve(n=1), or skin lesion(n=1) biopsy. One patient had CS enhancement, but only patchy enhancement over the foramen ovale and was diagnosed with an inflammatory condition after symptom and imaging resolution. One patient had a 4.8 cm CS mass and questionable foramen ovale involvement. Open cranial biopsy showed lymphoma.

Conclusions: In our series of 13 patients, PTC-TFOB obtained diagnostic tissue in 54%. This is the second largest reported series. We recommend PTC-TFOB for mass lesions that are clearly accessible by the foramen ovale. Lesions that only caused V3 enhancement or had questionable involvement of the foramen ovale were all non-diagnostic in our series.

Patient Care: This research clarifies when percutatnous transforamen ovale biopsy is likely to yield diagnostic results and when it is likely to fail.

Learning Objectives: By the end of this session participants should be able to understand when percutaneous transforamen ovale biopsy is likely to yield diagnostic tissue

References: Messerer, Mahmoud, et al. "Percutaneous biopsy of lesions in the cavernous sinus region through the foramen ovale: diagnostic accuracy and limits in 50 patients: Clinical article." Journal of neurosurgery 116.2 (2012): 390-398.