Huge Bilateral Pulmonary and Pleural Metastasis from Intracranial Meningioma: A Case Report and Review of the Literature

Abstract

A case of recurrent meningioma with atypical features and extracranial metastases is reported. A 34-year-old female was operated in 1996, 2000, and 2002, and frontal parasagittal meningioma was extirpated. Histological diagnoses of all the resected tumors were meningotheliomatous meningioma, WHO Grade I. However, 2 years later, the tumor recurred in the frontal scalp and was removed again totally. Histological diagnosis was reported as an atypical meningioma; meningotheliomatous type; WHO Grade II. She received radiation therapy. But the tumor had metastasized to the lung and pleura. Transthoracic tru-cut biopsy was performed from large mass of the left lung. Cytopathology was consistent with malignant meningioma, metastasis from the patient's known intracranial meningioma. Ki-67 staining index at the primary and metastatic sites of the present cases were 7 and 5%, respectively. We reviewed and discussed the histopathological features and mechanisms of metastasizing meningioma.

Malignant meningioma with extracranial metastases

“…The histological grade of the tumor is the most important predictive factor of recurrence or metastases 3,6,11 . A review of the histological descriptions of metastatic meningiomas showed that these tumors are predominantly of the papillary, atypical and malignant subtypes 3 .…”

“…A review of the histological descriptions of metastatic meningiomas showed that these tumors are predominantly of the papillary, atypical and malignant subtypes 3 . However, a high cell proliferation rate is not essential for the occurrence of extracranial metastases and any histologically benign meningioma can possibly metastasize 3,7 .…”

“…Histological evaluation of the lesion using a grading system that comprises mitotic figures, hypercellularity, nuclear pleomorphism and areas of necrosis helps predict recurrence or potential metastases 3,4 . Immunohistochemical analysis of a nuclear protein related to cell proliferation, Ki-67, is also useful to evaluate tumor agressiveness 3,4 . Tumors that are positive for Ki-67 tend to be more aggressive, with a higher chance of recurrence and/or metastases 4 .…”

“…Meningiomas are tumors originating from meningothelial cells of the arachnoid membrane and are benign in most cases [1][2][3] , corresponding to about 15% to 18% of all primary tumors of the central nervous system (CNS) 3,4 . Extracranial metastases of meningiomas are rare and occur in less than 1 per 1000 cases [3][4][5] .…”

“…Extracranial metastases of meningiomas are rare and occur in less than 1 per 1000 cases [3][4][5] . According to the WHO criteria, the histological grade of the tumor is the most important predictive factor of malignancy 6 .…”