Introduction: Whether patients with leptomeningeal metastasis (LM) exhibiting symptoms of hydrocephalus present with typical radiological findings, including Evans Index (EI) ≥0.3, callosal angle (CA) ≤90 degrees, disproportionately enlarged subarachnoid space hydrocephalus (DESH), and periventricular lucency, is not clear. This study aimed to investigate the radiological parameters in leptomeningeal metastasis-associtated hydrocephalus (LM-H) patients, assessing the presence of typical hydrocephalus parameters.
Methods: Radiologic parameters of EI, CA, DESH, and periventricular lucency were defined according to the 2021 Japanese guideline of normal pressure hydrocephalus. LM was classified as confirmed (positive CSF cytology or leptomeningeal biopsy), probable (clinical and neuroradiological evidence), or possible (clinical or neuroradiological evidence) according to the 2023 EANO-ESMO criteria. LM-H patients were defined as patients who had hydrocephalus symptoms with typical radiological findings or positive lumbar tap test. Statistical analysis was performed by SPSS 25 with a p-value < 0.05 as statistically significant.
Results: From March 2019 to April 2024, a total of 57 lung cancer LM-H patients (confirmed LM: 26, probable LM: 27, possible LM: 4) were included. Among all, the average age was 60.6 years. 49.1%, 49.1%, 25.8%, and 80.7% of patients presented with EI ≥0.3, CA ≤90 degrees, DESH, and periventricular lucency, respectively. Confirmed LM patients were significantly younger than the probable and possible group (p < 0.001). No statistically significant differences were found in EI, CA, and periventricular lucency among the three groups (p =0.92, 0.44, and 0.55, respectively). However, DESH appeared significantly less frequent in the confirmed and probable groups than the possible LM-H group (p =0.002). 50 patients (89.3%) had their symptoms improved 1-month after shunt surgeries.
Conclusion : EI < 0.3, CA >90, non-DESH, or lack of periventricular lucency should not be used to exclude hydrocephalus in LM patients. For patients clinically suspicious of LM, lumbar tap test should be considered even if typical hydrocephalus imaging features are absent.
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