A large Guyon's canal lipoma without neuropathy in a child.

Lipomas originating from Guyon's canal are uncommon tumors. There are rare reports of adult cases, often with nerve compression findings. However, so far, no report had described this tumor in the pediatric age group. This article presents an 8-year-old boy who presented with a 3-year history of slowly growing hypothenar mass. Exploration yielded a large lipoma (35×55×44 mm) originating from the proximal Guyon's canal, which resides within the hypothenar musculature. The lesion was excised totally, and histological evaluation confirmed the diagnosis. The follow-up period was uneventful, and complete cure was attained. To the best of our knowledge, this is the first report of a lipoma deriving from the Guyon's canal in a child. Despite its huge mass, no signs of nerve compression were detected. This inconsistency between children and adult patients may be due to anatomical and physiological differences of the Guyon's canal and attending nerves and muscles. In children, the structures forming the canal may be more expandable to let such a bulk grow without neuropathy.