Objective:

To describe the rapidly progressive course and diagnostic workup of a rare entity to narrow the practice gap for its timely diagnosis. 

Background:

A sixty-eight year old man with stage IV BRAF+ melanoma with metastasis to the intraparenchymal brain, on dabrafenib and trametinib treatment, presented with confusion after a fall out of bed.  He had been followed closely with stable treatment-related changes on surveillance brain MRIs and PET scans. Initial examination was remarkable for an acute left facial droop, disorientation, and reduced attention.

Design/Methods:

Case report.

Results:

A CTA of the head/neck did not reveal any acute changes and a motion-degraded MRI of the brain/cervical spine w/wo contrast revealed only scant, new blood in the occipital horns upon arrival. EEG did not reveal seizures but he was started on levetiracetam. Neuroleptic agents were not administered, but he developed asymmetric bilateral arm tremors worsened with action, increased tone throughout, and a one-time fever. Workup revealed acute, moderate hyponatremia and no systemic infection. His mental status continued to decline to the point of being somnolent, however, and he developed a Brudziński neck sign. Three lumbar punctures, including one with fluoroscopic guidance, had “dry taps” and high protein counts >600 mg/dL. A contrasted MRI of the entire neuroaxis revealed a complete lumbar block of CSF flow due to protein exudation from enhancing cervical and thoracic leptomeningeal lesions. CSF cytology evaluation was limited by scant cellularity but rare atypical cells were noted. The patient expired 10 days after admission while on comfort measures for his diagnosis of leptomeningeal carcinomatosis secondary to melanoma.

Conclusions:

About 5% of patients with melanoma will develop leptomeningeal disease, and there is no effective treatment. To our knowledge, only one other case report of RPD and EPS associated with leptomeningeal carcinomatosis exists and this is the first report of it associated with Froin’s syndrome.