Compressive Ulnar Neuropathy Caused by Olecranon Bursitis and Concomitant Epidermal Cyst: A Case Report.

Epidermal cyst is a dermal or subcutaneous epithelial cyst that contains keratin and is lined by true epidermis. Although extremely rare, it can cause pathology including nerve compression syndrome. We report a rare case of ulnar nerve compression in the elbow that was caused by olecranon bursitis and concomitant epidermal cyst in a 67-year-old man. The ulnar nerve was immediately adjacent to the olecranon bursa and was significantly compressed. There was no connection between the tumor and the ulnar nerve. Pain, numbness, and weakness in his ring and little fingers disappeared after resection of the cyst and bursa.