Metastases to Meckel's cave: report of two cases and comparative analysis of malignant tumors with meningioma and schwannoma of Meckel's cave.

OBJECTIVE: To investigate clinical characteristics of patients with malignant tumors of Meckel's cave with two illustrative cases. A comparative analysis of clinical features of malignant tumors of Meckel's cave with meningioma and schwannoma of Meckel's cave is discussed.

METHODS: We report two cases of malignant tumors involving Meckel's cave. We identified 19 additional cases of malignant tumors of Meckel's cave in the literature. We analyzed the symptoms, results of neurological and radiographic examination, pre-operative diagnosis and final diagnosis of these tumors. Our findings were then compared with well described case series of meningioma and schwannoma involving Meckel's cave.

RESULTS: Of the 21 patients with malignant tumor involving Meckel's cave, 76% (16/21) had pain, 67% (14/21) had paraesthesia, 89% (17/21) had objective evidence of trigeminal sensory involvement and 42% (8/21) had objective evidence of trigeminal motor involvement. In contrast, of patients with trigeminal schwannomas [1], only 23% presented with pain, 36% with paraesthesia, 74% with objective evidence of trigeminal involvement and 42% with trigeminal motor involvement. Pain and paraesthesia were seen more often in malignant tumors. In Delfini et al.'s [2] series of meningiomas involving Meckel's cave, 81% of patients presented with pain, 25% with paraesthesia, 63% with trigeminal sensory deficits and only 13% with trigeminal motor involvement. Patients with malignant tumors were more likely to be older, and have paraesthesia in comparison with patients with meningioma.

CONCLUSION: Subtle clinical clues may help differentiate malignant from benign involvement of Meckel's cave. We emphasize the need to thoroughly investigate patients early for a possible primary as well as metastases, in those found to have a lesion in the Meckel's cave.