We present a case of rapidly progressive hearing loss (SNHL) with leptomeningeal carcinomatosis (LC) and positive Zic4 antibodies. 

Rapidly progressive SNHL may be a presenting feature of central etiologies for SNHL, including leptomeningeal carcinomatosis¹. 

We present a case of rapidly progressive SNHL seen at Vancouver General Hospital, Vancouver, Canada. Informed consent for publication was obtained in accordance with AAN guidelines. 

A 72-year-old woman presented with rapidly progressive hearing loss documented on serial audiology without other focal neurological symptoms. Lumbar puncture revealed elevated protein, low glucose, and pleocytosis with poorly differentiated cells. MRI brain revealed gadolinium enhancement within the internal auditory canals bilaterally as well as the left cochlea. A malignancy screen revealed poorly differentiated breast adenocarcinoma, with identical cells to those in the cerebrospinal fluid. Paraneoplastic antibody panel was positive for Zic4 antibodies in the serum and CSF. 

We present a case of rapidly progressive bilateral SNHL who was found to have leptomeningeal carcinomatosis and Zic4 antibodies. To our knowledge, this is the first case of both LC and SNHL. The ZIC family of genes play a role in cerebellar development. Zic4 antibodies have reported with paraneoplastic cerebellar degeneration^2,3. Animal models have demonstrated a role of the ZIC family in inner ear development⁴. In this case, the presence of Zic4 antibodies may represent an epiphenomenon to tumor cell deposits in the inner ear.