Objective:

To report a unique possibility of chronic cavernous sinus thrombosis becoming symptomatic years after the original insult, which is unusual as cavernous sinus thrombosis typically presents acutely with symptoms.

Background:

Cavernous sinus thrombosis is a rare, life-threatening medical emergency that may affect multiple cranial nerves including CNIII, CNIV, CNV1, CNV2, and CNVI, with CNVI being the most commonly affected.

Design/Methods:

A 66-year-old female has history of metastatic breast cancer and metastatic renal cell carcinoma to the right mesial temporal lobe and to the right Meckel’s cave, treated with chemotherapy and radiation. She was previously known to have decreased contrast enhancement in the right cavernous sinus, but no associated symptoms. Three years after the right cavernous sinus abnormality was first detected, she presented with progressive monocular esotropia in the right eye.

Results:

Neurologic exam revealed an isolated right CN VI (abducens nerve) palsy without any other cranial neuropathies. MRI and MRV of the orbit were performed and demonstrated diffuse hypoenhancement of the right cavernous sinus, unchanged over multiple prior MRIs, suspicious for chronic thrombosis. Post-radiation changes from the treated metastasis to the right medial temporal lobe remained stable. There was no enhancement of CNVI. She was started on anticoagulation given the concern for the cavernous sinus thrombosis causing cranial nerve palsy, but the right eye esotropia continued to worsen over the course of several weeks. Alternative etiologies, including intracranial hypertension, microvascular CNVI palsy unrelated to the thrombosis, radiation-induced neuropathy, myasthenia gravis, direct infiltration of neoplasia, complications from checkpoint inhibitor agents, and nutritional deficiency were considered. Ultimately, the cavernous sinus thrombosis was thought to the most likely cause of the severe CNVI palsy.

Conclusions:

This case illustrates the possibility of a chronic cavernous sinus thrombosis becoming symptomatic years later, a phenomenon not well documented in the literature as cavernous sinus thrombosis typically presents acutely with symptoms.