Intracranial metastasis or meningioma? An uncommon clinical diagnostic dilemma.

Background: Cerebral metastases are the most frequent brain tumors in adults and they may occasionally present as an isolated meningeal mass, suggesting a meningioma. Because of the prognostic relevance in discriminating both tumors, we review the literature and analyze four patients in whom the diagnosis of meningioma was initially made.

Case Description: Four cases of isolated meningeal metastases are presented and in all of them a meningioma was considered as the main preoperative diagnosis. Only one patient had a history of previous cancer. The primary tumors found after pathological testing of the lesions were thyroid carcinoma, prostate adenocarcinoma, breast adenocarcinoma, and hypernephroma. The clinical and neuroimaging features as well as the differential diagnoses are discussed. The literature regarding these forms of meningeal metastases was reviewed.

Conclusions: Although they are uncommon, dural metastases can be mistaken for meningiomas. Our experience in these cases has led us to consider ordinary metastases as a differential diagnosis even when a meningioma is suspected. The definitive diagnosis of a meningioma should be established only after the histopathological report has been analyzed.