Diagnosis and outcome of biopsies of indeterminate lesions of the cavernous sinus and Meckel's cave: A retrospective case series in 85 patients

Background: When clinical presentation, laboratory studies, or imaging cannot diagnose cavernous sinus (CS) and/orMeckel's cave (MC) lesions, biopsy may be necessary. Objective: To review our institutional series of biopsies of indeterminate CS and MC lesions. Methods: Records from January 1994 to June 2016 were searched for biopsied indeterminate CS and MC lesions. We defined indeterminate as having an atypical imaging appearance or a broad differential and the need for tissue for definitive diagnosis. We defined primary tumors as originating from cells inherent or near the CS and MC. Results: Eighty-five patients were included (median age 59 [2-85] yr); 22 (28%) had a cancer history. Approaches included frontotemporal craniotomy (n=48, 56%), endoscopic endonasal (n = 20, 24%), percutaneous transforamen ovale (n = 12, 14%), or retrosigmoid craniotomy (n = 5, 6%). Final diagnosis was metastatic in 27 (32%), primary in 21 (25%), inflammatory in 13 (15%), hematologic in 11 (13%), fungal in 5 (5%), and nondefinitive or nondiagnostic in 8 (10%) patients. Thirteen (59%) patients with a cancer history (n = 22) had a diagnosis consistent with their prior cancer; the remaining had a second pathology (n=6, 27%) or nondiagnostic biopsy (n=3, 14%). Two patients had surgical complications resulting in death. Conclusion: In this patient cohort, metastatic tumors were the most likely pathology. The biopsy threshold should be lower in patients with a cancer history if clinical or radiographic diagnosis is uncertain as 27% had a second disease. However, we consider biopsy as a last resort because the risk of major morbidity/mortality, while low, is not zero.