Band-Like Brainstem Lesion in a Patient With a History of Lung Adenocarcinoma

Leptomeningeal metastasis (LM) is a severe complication of primary malignancy that has spread to the leptomeninges and cerebrospinal fluid (CSF). Here, we report a patient whose magnetic resonance imaging (MRI) showed a unique brainstem lesion suspicious of LM. A 72-year-old man presented with dizziness, gait instability, and cognitive decline, primarily object naming. He had a history of lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutation. Brain MRI revealed a band-like lesion surrounding the ventral brainstem with T2 weighted-image/fluid attenuation inversion recovery (FLAIR) imaging and diffusion-weighted imaging (DWI) hyperintensity without gadolinium enhancement. No malignant cells were detected in the CSF. He underwent ventriculoperitoneal shunt two months after the onset, and his gait improved, but his cognitive function declined further. Recent reports suggest similar brainstem lesions as a unique LM pattern, which occurs almost exclusively in patients with lung adenocarcinoma with EGFR mutation. Therefore, if MRI shows this brainstem finding, repeated and appropriate CSF cytology is needed to detect tumor cells. Furthermore, if a patient with lung adenocarcinoma shows a cognitive decline, cerebral LM and auto-antibodies that mainly target neuronal surface antigens should be considered.

[Diagnosis and Treatment of Leptomeningeal Metastasis in Non-small Cell Lung Cancer]

Leptomeningeal metastasis (LM) is one of the disastrous events in managing advanced non-small cell lung cancer (NSCLC) due to severe clinical symptoms and a grave prognosis. Although intrathecal (IT) chemotherapy show some effects for LM in advanced NSCLC, the prognosis is still poor (12 wk-14 wk). A large majority (84%-97%) of the patients were found to have adenocarcinoma histology. Epidermal growth factor receptor (EGFR) senstive mutations were detected in 43.0%-70.5% adenocarcinoma patients with LM. EGFR tyrosine kinase inhibitors (TKIs) showed to be effective for LM in selected NSCLC patients in some reseaches, and confer a survival benefit. Furthermore, future trials need be done to determine the effect of EGFR-TKIs treatment in NSCLC-LM patients.