Teaching NeuroImage: Bloomy Rind Sign of Leptomeningeal Carcinomatosis

A 68-year-old woman presented with vertigo, nausea, and vomiting for 3 days. She had lung adenocarcinoma with EGFR mutation (p.L858R) for 1 year and was in remission after osimertinib treatment. Neurologic examination revealed stiff neck, horizontal and vertical nystagmus, dysphagia, and bilateral Babinski signs. MRI revealed a symmetrical hyperintensity along the surface of the midbrain, pons, and cerebellar peduncles in T2, fluid attenuated inversion recovery, and diffusion-weighted imaging (Figure 1). T1 and apparent diffusion coefficient were normal, and there was no contrast enhancement. No significant supratentorial anomaly was found. CSF cytology identified cancer cells carrying EGFR mutation (p.L858R). We added bevacizumab to osimertinib. MRI 2 months later revealed thickened lesions expanded to the medulla and inner ears with hydrocephalus (Figure 2). The patient finally died because of respiratory failure. In leptomeningeal carcinomatosis, common MRI findings are linear enhancement of the sulci, leptomeninges, and nerve roots, whereas bloomy rind sign, possibly induced by tumor infiltration, cytotoxic edema, and microinfarction, is rare and characteristic.(1,2)