Missing the Mark: CSF CA 19-9 secures diagnosis of rare Pancreatic Leptomeningeal Carcinomatosis
Sydnie Jones1
1BAMC Neurology residency
Objective:

- The viewer will appreciate the epidemiology and clinical features of Pancreatic Leptomeningeal Carcinomatosis

- The viewer will appreciate radiologic and laboratory findings associated with Leptomeningeal Pancreatic Carcinomatosis 
Background:

There exists very few reports of carcinomatosis in patients with pancreatic cancer. Leptomeningeal carcinomatosis (LC) is a rare complication in which there is seeding of the leptomeninges by cancerous cells. LC is estimated to occur in 3% to 8% of solid tumors. It can cause a variety of neurologic complaints including meningitis signs, headache, dizziness, or nausea. Obtaining CSF for pathologic interrogation remains standard for diagnosis, but other avenues such as cell marker evaluation exist. Here, we describe a case of LC confirmed with CSF CA 19-9 and high sensitivity cytology.

Design/Methods:
NA
Results:

CASE REPORT:

A 55-old male with Stage IV pancreatic adenocarcinoma s/p chemotherapy who presented due to chronic progressive headaches, nausea and vomiting. Initial MRI demonstrated diffuse leptomeningeal enhancement around the brain, cervical and thoracic cord with CSF analysis showing normal chemistry and initial CSF cytology was negative. His symptoms persisted and interval MRI revealed extensive worsening of his leptomeningeal enhancement. After repeated lumbar punctures, his CSF had 15 times the elevated tumor marker CA 19-9 in comparison to serum and high sensitivity cytology revealed KRAS mutation, an exon 2 missense variant.

Conclusions:

LC is an extremely rare complication of pancreatic cancer that unfortunately carries with it high morbidity and mortality. The diagnosis can be challenging as identification of malignant cells in the CSF often requires repeated analyses. Our patient had high levels of tumor marker CA 19-9 in the CSF which may be a useful adjunct to identification when clinical suspicion remains elevated in the setting of negative cytology.

10.1212/WNL.0000000000204128