An unusual presentation of carcinomatous meningitis

A 67-year old previously well male presented with a 1 week history of confusion on a background of 3 weeks of headache. Past history included two superficial melanomas excised 5 years ago. Treatment for meningoencephalitis was commenced based on lumbar puncture (LP) and non-contrast brain magnetic resonance imaging (MRI) results. Lack of a clinical response to antibiotics resulted in a second LP and contrast brain MRI which demonstrated hydrocephalus and leptomeningeal disease. Ongoing deterioration led to a whole-body computed tomographic and spinal MRI that showed widespread metastatic disease and extensive leptomeningeal involvement of the spinal cord. The diagnosis of metastatic melanoma with carcinomatous meningitis was made based on cytological analysis of cerebrospinal fluid. He died 2 weeks later in a palliative care facility. This case illustrates that the diagnosis of carcinomatous meningitis can be difficult to make as the heterogeneous nature of its presentation often delays the diagnosis.