Introduction: Intraneural ganglions are benign and rare mucinous cysts that originate within peripheral nerves and typically can lead to symptoms and signs of peripheral neuropathy. The most common location is the peroneal nerve, and the second most common location is the ulnar nerve.
Case Presentation: We present a case of a 53-year-old man who presented with increasing numbness in the ulnar aspect of the left hand and decreasing hand strength. MRI showed an intraneural ganglion, and as the patient had clinically progressive symptoms, a decision was made for surgical excision. The patient was symptom-free after the procedure and had no neurological deficits. Eighteen months later, the patient contacted us again as his symptoms had returned. A new MRI showed ganglion recurrence. Due to progressive clinical symptoms, another attempt was made to remove the ganglion surgically. Paraffin immunostains excluded other diagnoses like synovial cyst, posttraumatic neuronal cyst, Tarlov cyst, mesothelial cyst, and cystic lymphangioma. At follow-up 3 months postoperatively, the patient was symptom-free and had normal neurological findings.
Conclusion: Intraneural ganglion should be considered as a differential diagnosis of a cystic mass close to a nerve. For surgery, we favor less radical methods, such as simple decompression.