The Bloomy Rind Sign: A Key MRI Marker in Leptomeningeal Carcinomatosis From Lung Adenocarcinoma

A 48 year-old female with a history of metastatic lung adenocarcinoma to the brain presented with acute onset dizziness for 12 hours. The neurological exam was notable for subtle sustained nystagmus on right and upward gaze. A code stroke was called and CT brain revealed no acute intracranial abnormality. MRI brain demonstrated new subtle restriction diffusion and FLAIR hyperintensity along the anterior surface of the brainstem and the middle cerebellar peduncles without evidence of enhancement, concerning for leptomeningeal disease. The remainder of the supratentorial metastases were stable. Lumbar puncture was performed and CSF analysis confirmed metastatic adenocarcinoma.