Objective To investigate the clinicopathological features of pulmonary adenocarcinoma-to-meningioma metastasis with meningeal carcinomatosis, and to reduce the rate of missed diagnosis of this disease. Methods and Results A 58-year-old female was admitted to hospital due to repeated headaches for 4 years and increased dizziness and vomiting for 2 months. Head MRI showed a space-occupying lesion in left apical petrous cross middle posterior fossa (mainly in the posterior fossa). Microscopy showed the tumor was mainly composed of meningothelial meningioma. In addition, the implantation of adenocarcinoma cells on the surface of arachnoid, and the small tumor adenocarcinoma nests in the meningioma were found. The cerebrospinal fluid cytology found heterotypic tumor cells. Immunohistochemical staining showed meningioma components expressed progesterone receptor (PR), somatostatin receptor 2 (SSTR2), Ki-67 proliferation index was 3%; adenocarcinoma components express cytokeratin (CK), cytokeratin 7 (CK7), thyroid transcription factor-1 (TTF-1), aspartic protease A (Napsin A), Ki-67 proliferation index was 30%. Epithelial membrane antigen (EMA) was stained of two components. Final pathological diagnosis was pulmonary adenocarcinoma-to-meningioma metastasis with meningeal carcinomatosis. Conclusions Pulmonary adenocarcinoma-to-meningoma metastasis is uncommon, So far, there are 20 cases reported. It is common in the elderly, mostly in women, with poor prognosis. Accurate diagnosis depends on histopathological, and should be combined with clinical, imaging, cerebrospinal fluid cytology, multidisciplinary diagnosis can avoid missed diagnosis.