This case illustrates a meningioma incidentally found during oncologic staging for a lung carcinoma. 

In a period of months, this meningioma demonstrated large increase in its volume together with the development of two new cerebral ring enhancing lesions that had imaging characteristics favoring metastases. The prominent increase of the right middle cranial fossa lesion raised the suspicion for an atypical meningioma or a metastatic involvement to this known vascularized tumor. 

The patient was submitted to the resection of this lesion which showed to be a metastatic carcinoma within the right middle cranial fossa meningioma.  

This condition is well known and referred as a tumor-to-tumor metastasis.