Intraneural ganglion of the ulnar nerve

We report the case of a 76-year-old right-hand dominant man with hypertension and type 2 diabetes mellitus who presented with numbness of the right ring and little fingers for 8 months and a palpable mass lesion in the right forearm for 3 months before his hospital visit. The patient exhibited grip power weakness and atrophy of intrinsic muscles. Magnetic resonance imaging confirmed a well-defined oval mass of 1.5 × 0.6 × 0.6 cm³ between the ulnar bone and nerve. This lesion was hyperintense on T2-weighted images and isointense on T1-weighted images. A zigzag incision was made for ulnar nerve exposure, and the tumor lesion was identified and carefully excised with minimal damage of ulnar nerve. A cystic mass invaded ulnar nerve extending approximately 1.5 cm was resected and reconstructed by sural nerve grafting. The patient was examined 6 months after surgery. His grip power and muscle strength increased, and no numbness or pain was detected. The outcome of this case suggests a potential surgical benefit exists even in cases of apparent chronic or severe denervation atrophy and that ganglion excision and nerve grafting should be considered.