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Compression of the ulnar nerve in Guyon's canal caused by a large hypothenar cyst
Adam Sierakowski1, Claire Jane Zweifel, Simon Payne
1St Andrew's Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, United Kingdom. adamsiera@yahoo.co.uk
Objective:
We report the case of a 77-year-old man who presented with a long-standing, large swelling of the left hypothenar eminence. This was associated with recent-onset paresthesia and numbness of the ring and little fingers. Magnetic resonance imaging demonstrated a cystic lesion that occupied almost the entire bulk of the hypothenar eminence.
Methods:
Surgical exploration revealed a 7-cm, encapsulated, yellow-brown cyst, around which were stretched the superficial sensory branches of the ulnar nerve. The hypothenar musculature lay flattened against the deep border of the mass.
Results:
The cyst was removed and Guyon's canal was released. Histologic examination confirmed a large cyst containing proteinaceous debris and blood breakdown products. It might have resulted from hemorrhage into a long-standing ganglion. Removal of the cyst led to full resolution of the patient's symptoms.
Conclusions:
This represents an unusual cause of ulnar tunnel syndrome. It is rare to encounter such a large cyst in the hand and interesting in the sense that the resulting symptoms were relatively mild and took many years to develop.
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