The bloomy rind sign: A key imaging clue in early leptomeningeal carcinomatosis from lung cancer—A case report

Leptomeningeal carcinomatosis (LMC) is a rare but serious complication of advanced cancer, occurring in approximately 5% of patients with metastatic disease. It results from the dissemination of malignant cells into the cerebrospinal fluid and leptomeninges, often presenting with nonspecific neurological symptoms. We report a case of a 46-year-old male with no prior cancer history who presented with progressive headaches, vomiting, and cranial nerve deficits. MRI revealed the "bloomy rind sign"-a curvilinear T2-FLAIR hyperintensity surrounding the brainstem-suggestive of early LMC. Further imaging identified a hilar pulmonary mass consistent with lung cancer. Despite treatment with intrathecal chemotherapy and corticosteroids, the patient's condition deteriorated rapidly. This case underscores the diagnostic importance of the bloomy rind sign in early-stage LMC and highlights the need for heightened clinical suspicion and timely neuroimaging in patients with atypical neurological symptoms.