RESUMEN
Cubital tunnel syndrome is the second most common neuropathy of the upper extremity. Cubital tunnel syndrome caused by intraneural ganglion cysts is rare in clinical practice. We present the case of a 71-year-old male patient with a 4-month history of cubital tunnel syndrome of the left elbow due to an intraneural ganglion cyst. After revision of the ulnar nerve and resection of the intraneural cyst nearly complete recovery was achieved within a 5 month follow-up but some sensory deficits of the fifth fingertip. We recommend preoperative ultrasound examination of the cubital tunnel even in cases with clear diagnosis. Ganglion cyst as a cause of cubital tunnel is rare but needs to be diagnosed and treated as soon as possible to prevent irreversible complications.