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

Abstract

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.

TWEETABLE ABSTRACT

A non-enhancing, T2 FLAIR hyperintense, diffusion-restricting brainstem lesion in an EGFR-positive lung cancer patient may represent an early indicator of leptomeningeal metastases.

Executive summary

• Lung cancer patients harboring EGFR mutations are at a higher risk of leptomeningeal metastases compared with EGFR wild-type patients.

• Leptomeningeal metastases may go undetected due to the decreased sensitivity of cerebral spinal fluid cytology and magnetic resonance imaging.

• An exceedingly rare non-enhancing, T2-hyperintense, diffusion-restricting ventral brainstem imaging finding may be an early indicator of leptomeningeal metastases.

• Osimertinib, a third generation EGFR TKI, may be effective in treating this brainstem lesion, obviating or deferring the need for whole-brain radiation therapy.

Keywords: :

• brainstem
• diffusion restriction
• EGFR
• leptomeningeal carcinomatosis
• leptomeningeal metastases
• MRI
• non-enhancing
• non-small cell lung cancer
• osimertinib
• T2 FLAIR hyperintensity

Acknowledgments

The authors would like to thank J Kaur for her presentation on this case.

Author contributions

C Yuen: study concept, data collection, analysis, interpretation, and final approval. S Bao: data collection, analysis, interpretation, manuscript revision, and final approval. X Kong: manuscript revision and final approval.

Financial disclosure

X Kong received an honorarium from Zai Lab for invited speeches for symposiums prior to July of 2021. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Competing interests disclosure

The authors have no competing interests or relevant affiliations with any organization or entity with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, stock ownership or options and expert testimony.

Writing disclosure

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval (#) and/or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations.

In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.