Anti-CRMP5 optic neuropathy associated with oral squamous cell carcinoma

Background

Paraneoplastic optic neuropathy is a rare condition typically linked to small-cell lung cancer. This report presents the first known case of such neuropathy associated with squamous-cell carcinoma of the tongue, highlighting the importance of considering atypical etiologies in the differential diagnosis of optic neuropathy.

Design/methods

Case Report

Results/case presentation

A 64-year-old smoker presented with progressive, bilateral, painless visual loss over a month. An eye exam revealed decreased visual acuity and bilateral optic disk edema. Initial external magnetic resonance imaging (MRI) showed minimal enhancement of the optic nerves, raising concerns for optic neuritis. The patient received five days of high-dose intravenous corticosteroids without improvement. Over the next two months, she progressed to a near-total visual loss. Blood tests revealed non-specific polyclonal antibody elevations, and cerebrospinal fluid (CSF) analysis demonstrated pleocytosis and negative infectious workup. Anti-CRMP-5 IgG antibodies (ab) were identified in CSF and serum. Positron emission tomography (PET) scan showed a small focus of hypermetabolism in the left oral cavity and adjacent cervical lymph node. The biopsy identified squamous cell carcinoma of the tongue. High-dose IV steroids and plasmapheresis resulted in minimal visual improvement only. The patient underwent the surgical removal of the primary tumor, and through four years of follow-up, no other malignancies were discovered.

Conclusions

To our knowledge, this is the first case report of anti-CRMP5 paraneoplastic optic neuropathy in the setting of squamous cell carcinoma of the tongue. Paraneoplastic etiologies should be considered in the differential diagnosis of optic neuropathy, particularly in older smoker patients.