Meningeal carcinomatosis presenting with leukoencephalopathy-like imaging findings.

Meningeal carcinomatosis is a unique and rare form of metastasis observed in patients with malignant tumours. Diagnosis is simple when the primary lesion of the malignant tumour is clear, and when multiple miliary lesions are confirmed via cranial contrast MRI; however, many patients exhibit atypical imaging findings. In the present report, we discuss the case of a 72-year-old man who presented with subacute consciousness impairment and MRI findings suggestive of progressive, bilateral leukoencephalopathy-like lesions around the ventricles. Idiopathic hydrocephalus was initially suspected due to increased cerebrospinal fluid (CSF) pressure accompanied by normal cell counts. Although the patient underwent a ventriculoperitoneal shunt operation, his symptoms did not improve. Whole-body CT revealed findings suggestive of adenocarcinoma in the left lung. Paraneoplastic syndrome was suspected, and he was treated with three courses of high-dose intravenous methylprednisolone. However, his neurological symptoms did not improve, and he died 2 months after admission. The patient was ultimately diagnosed with meningeal carcinomatosis due to lung adenocarcinoma upon autopsy. In this case, we suspected that the white matter lesions observed on MRI resulted from secondary hydrocephalus due to obstruction of the CSF circulation. This is the first reported case of progressive leukoencephalopathy-like imaging findings in a patient with meningeal carcinomatosis.