Tumor to tumor metastasis: adenocarcinoma of lung metastatic to meningioma.

Tumor-to-tumor metastasis (T2Tmets) is an established entity but often overlooked and underdiagnosed. Merely 84 such cases are reported in literature till date. The authors here describe a 65-year-old man presenting with first episode of focal seizure and incidentally turned out to be a case of adenocarcinoma of lung metastatic to a meningioma. The diagnosis of T2Tmets was based solely on histopathological criteria. Recent advent of brain imaging revolutionized its diagnosis and it has moved from the realm of thologists to that of radiologists. In our case, diagnosis was also established by immunohistochemistry.