P06.03 * CASE REPORT OF A METASTASIS OF SQUAMOUS CELL LUNG CARCINOMA INTO AN INTRACRANIAL MENINGIOMA

Abstract

INTRODUCTION: Rare cases of tumor-to-meningioma metastases have yet been reported before. Cancer metastasis into a meningioma is a rare and often incidential finding. The most commonly reported malignancies are breast and lung cancer. Meningiomas are the most common intracranial lesion to host metastatic tissue and meningiomas seem to provide a favorable environment for metastatic seeding. Several factors responsible for tumor metastasis into meningioma have been proposed :meningiomas are highly vascular and also grow slowly. In addition their high collagen and lipid content seems to be supportive to the seeding and growing of malignant cells. Also, meningeomas express binding proteins which may also play a role in metastatic seeding. CASE REPORT: A 73-year-old woman was admitted because of progression with a 3-week history of her former of left sided arm weakness. She had undergone a right upper lobectomy for poorly differentiated sqamous cell carcinoma of the lung 3 months ago. AnMRIscan of the brain revealed a lesion the size of 3.5 cm on the right parietal side. It was adhering to the dura mater, which suggested an extraaxial origin of the tumor and meningeoma was suggested. The lesion showed significant contrast agent uptake and was surrounded by peritumoral edema. A surgical removal of the lesion was performed. Histologic analysis showed a secretory meningioma (WHO grade I) highly infiltrated with metastatic cancer cells of a poor-differentiated squamous cell carcinoma. The focus within the meningeoma stained positive for p16, CK 5/6, p63/HMW-CK, CK AE 1/3 and negative for TTF-1, Ki-67. The patient was treated with postoperative cerebral radiation theraphy. A CT staging of the chest and abdomen was performed and revealed new blastomatoid lesions of the lung, liver and the left adrenal gland. The general condition of the patient deteriorated fast in the following weeks and she died two months after surgery as a result of the reactivation of the malignant squamous cell lung carcinoma. DISCUSSION: The phenomenon of tumor to tumor metastasis is defined by two criteria: The metastatic focus must be encased by a rim of histologically distinct tumor tissue and a proven primary carcinoma that is compatiblewith the metastasis. In this patient,anintracranialmeningeomawasthe target for the seeding of a malignant systemic cancer. Given the comparatively large number of patients with meningeoma and even larger number of persons with cancer this coincidence could be seen higher than reported. The practical issue is to identify future factors to identify patients with cancer metastasis into meningioma to improve therapeutic strategies.