Abstract

We present a rare case of trigeminal amyloidoma arising in a 50-year-old man presenting with progressive numbness and paraesthesia affecting the V2 and V3 distribution of his left trigeminal nerve. On examination, he was found to have wasting of the temporalis and masseter muscles and loss of sensation in the V2 and V3 dermatomes. Imaging revealed a focal lesion in Meckel's cave, presumed to be a possible schwannoma. A suboccipital craniotomy was performed which revealed “plump”, reddish nerve fascicles but no discrete tumour. Several fascicles in the lateral part of Meckel's cave were excised. Microscopic results showed a small segment of well-myelinated peripheral nerve infiltrated by confluent masses of tissue staining intensely positive with Congo red. Immunostaining was positive for lambda and transthyretin. These staining features were supportive of a diagnosis of amyloidoma. Amyloidomas involving the gasserian ganglion or trigeminal nerve are extremely rare; only 12 cases have been reported. These patients require complex pain management to treat their symptoms and we will discuss up-to-date management of these complex issues.