Cryptic angiomas, which are intrinsic to cranial nerves, are uncommon. Such lesions involving the trochlear nerve have not been previously described. The authors have therefore found it interesting to report a case fortuitously discovered in a patient with trigeminal neuralgia who underwent a fifth nerve microvascular decompression through the supracerebellar space. The angioma was not responsible for the neuralgia, but because of its potential risk of bleeding, the lesion was treated by resection of the trochlear nerve in its invaded portion. Then, the nerve was successfully repaired with an autograft harvested from the distal part of the sural nerve.