FLAIR hyperintensity along the brainstem surface in leptomeningeal metastases: a case series and literature review

"Bloomy rind sign" in varicella-zoster virus brainstem meningoencephalitis

The bloomy rind sign, characterized by band-like abnormalities along the surface of the brainstem on magnetic resonance imaging without contrast enhancement, has been considered a specific imaging marker for leptomeningeal metastasis from lung adenocarcinoma. In this study, we describe the case of an 85-year-old male with a 3-week history of headache, fever, and progressive cognitive impairment. The patient was diagnosed with varicella-zoster virus brainstem meningoencephalitis and magnetic resonance imaging revealed hyperintensities along the brainstem surface on fluid-attenuated inversion recovery and diffusion-weighted imaging that mimicked a bloomy rind sign. However, the patient showed no signs of lung cancer or meningeal carcinomatosis. This case suggests that the bloomy rind sign is not exclusive to leptomeningeal metastasis but can also be observed in other conditions, such as central nervous system infections.

A non-enhancing, T2 fluid-attenuated inversion recovery hyperintense, diffusion-restricting brainstem lesion in an EGFR tyrosine kinase inhibitor-treated non-small-cell lung cancer patient

Leptomeningeal metastasis (LM) is a devastating complication of malignancy. Diagnosis relies on both contrast enhancement on imaging and malignant cells in cerebral spinal fluid cytology. Though early detection and prompt intervention improves survival, the detection of LM is limited by false negatives. A rare brainstem imaging finding uncovered specifically in EGFR mutation-positive lung cancer patients may represent an early sign of LM. This sign demonstrates high signal on T2 fluid-attenuated inversion recovery and diffusion-weighted imaging sequences, but paradoxically lacks correlative contrast enhancement. Here we report a case of a 72-year-old female EGFR-positive lung cancer patient who developed this lesion following treatment with two first-generation EGFR tyrosine kinase inhibitors then showed subsequent response to osimertinib, an irreversible third-generation EGFR tyrosine kinase inhibitor.

Extraordinary linear non-enhancing brainstem leptomeningeal metastasis from lung adenocarcinoma: A case report

In patients with lung adenocarcinoma, angiogenesis-altering drugs can alter the appearance of leptomeningeal metastasis on magnetic resonance imaging (MRI) scans. In the ventral brainstem, this can manifest as a unique, linear, non-enhancing T2-hyperintense signal.

Development and validation of a nomogram to predict leptomeningeal metastases in lung adenocarcinoma: Cervical lymph node metastasis is an important association factor

BACKGROUND

The goal of this study was to create a nomogram using routine parameters to predict leptomeningeal metastases (LMs) in advanced lung adenocarcinoma (LAC) patients to prevent needless exams or lumbar punctures and to assist in accurately diagnosing LMs.

METHODS

Two hundred and seventy-three patients with LMs and brain metastases were retrospectively reviewed and divided into derivation (n = 191) and validation (n = 82) cohorts using a 3:7 random allocation. All LAC patients with LMs had positive cerebrospinal fluid cytology results and brain metastases confirmed by magnetic resonance imaging. Binary logistic regression with backward stepwise selection was used to identify significant characteristics. A predictive nomogram based on the logistic model was assessed through receiver operating characteristic curves. The validation cohort and Hosmer-Lemeshow test were used for internal validation of the nomogram.

RESULTS

Five clinicopathological parameters, namely, gene mutations, surgery at the primary lung cancer site, clinical symptoms of the head, N stage, and therapeutic strategy, were used as predictors of LMs. The area under the curve was 0.946 (95% CI 0.912-0.979) for the training cohort and 0.861 (95% CI 0.761-0.961) for the internal validation cohort. There was no significant difference in performance between the two cohorts (p = 0.116). In the internal validation, calibration plots revealed that the nomogram predictions were well suited to the actual outcomes.

CONCLUSIONS

We created a user-friendly nomogram to predict LMs in advanced lung cancer patients, which could help guide treatment decisions and reduce unnecessary lumbar punctures.

Partially Reversible FLAIR Hyperintensity Along the Brainstem Surface in Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy

A 41-year-old woman presented with headache, fever, irritability, and confusion. She developed a coma after admission. MRI of the brain revealed periventricular and deep white matter lesions. Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging hyperintensity along the brainstem surface was observed (Figure 1), considered a rare but characteristic finding in leptomeningeal carcinomatosis from lung cancer.1,2 However, serum tumor markers, CSF cytopathology, contrast-enhanced high-resolution chest CT, and whole-body PET were negative. Antiglial fibrillary acidic protein antibodies (cell-based assay) were positive in serum and CSF. After receiving intravenous methylprednisolone and immunoglobulin, the symptoms improved significantly. Repeated MRI of the brain showed partial resolution of the lesions (Figure 2). The lesions were possibly induced by immune-mediated intramyelinic edema.

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.

Band-like hyperintensity along the ventral surface of the brain stem on FLAIR and DWI in leptomeningeal carcinomatosis of lung adenocarcinoma

Since leptomeningeal carcinomatosis is rarely observed before diagnosis of the primary cancer, its detection is often delayed. We report the case of a 60-year-old woman who presented with lung adenocarcinoma with leptomeningeal carcinomatosis. Magnetic resonance imaging showed the characteristic abnormal hyperintensity along the ventral surface of the brain stem on fluid-attenuated inversion recovery and diffusion weighted imaging. It had no contrast uptake. Based on these findings, we were able to make an early diagnosis of leptomeningeal carcinomatosis of lung adenocarcinoma. This condition was resolved after treatment with a tyrosine kinase inhibitor.