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Cerebral cavernous malformations (CCMs) incidence ranges between 0.3 to 0.5%. Of those, less than 1% affect the optic pathway (OP), with the chiasm being most commonly affected. Most CCMs are sporadic, solitary lesions. In its autosomal dominant (AD) familial form, cavernomas can be caused by heterozygous germline loss of-function mutations in genes CCM1/KRIT1, CCM2/Malcavernin, or CCM3/PDCD10. The founder mutation involving KRIT1 accounts for disease in Hispanic Americans, and this is the first OP cavernoma described in the literature in this population.

A 40-year-old man with uncontrolled hypertension, originally from Cuba, presented with acute onset vision loss OS. He reported a history of mild vision loss OS in 2008 with spontaneous recovery and residual vision deficit. Over years, he had episodes of mild vision loss OS where he did not seek medical attention. In December of 2022, he presented to our institution with acute onset vision loss OS associated with retroorbital pain increasing with eye movements. Due to initial concern for optic neuritis, IV methylprednisolone was started, without response. Examination showed severe vision loss, a dense RAPD, and optic atrophy OS, indicating a severe optic neuropathy OS which was confirmed by OCT (Optical Coherence Tomography). Imaging showed a heterogenous, multilobulated, hyperintense left optic nerve sheath lesion in the context of intraparenchymal lesions with similar characteristics (“popcorn”), suggesting an optic nerve cavernoma. In lieu of biopsy or resection, our patient underwent genetic testing with DNA sequence analysis showing a pathogenic variant (c.1261A>T) in the KRIT1 gene that is associated with AD CCM, also known as familial CCM.

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While mostly CCMs are sporadic, its AD familial form can be caused by mutations in several genes including CCM1/KRIT1. In Hispanic Americans KRIT1 mutation is responsible for the disease process and this is the first case of optic nerve cavernoma in this population.