Microbial keratitis as the manifestation of trigeminal amyloidoma at initial presentation

Amyloidosis is characterized by the deposition of extracellular, insoluble proteinaceous, fibrillar material. It can be classified as primary, in cases without underlying disease, or secondary, in cases with an associated chronic disease (e.g., multiple myeloma, rheumatoid arthritis, osteomyelitis, or tuberculosis). Isolated amyloidoma rarely involves the central nervous system but has been reported to occur in the orbit, spine, pituitary gland, jugular foramen, cerebellopontine angle, and cerebral white matter. In the literature, only five reports could be found of amyloidoma involving the trigeminal ganglion. This is a report of a case of trigeminal nerve amyloidoma that had initial symptoms of microbial keratitis secondary to trigeminal neuropathy. A review of the literature on amyloidoma of the trigeminal nerve is included.