Author: Dr Ian Coulson, Consultant Dermatologist and Editor-in-Chief, 2022.
Edited by the DermNet content department
This 55-year-old woman has developed a groove along one of her fingernails. She has noticed intermittent discharge from underneath the cuticle of a clear, sticky material.
The groove has been caused by pressure from a myxoid cyst (digital mucous cyst) which overlies the nail matrix. Pressure applied to the nail matrix from any cause will result in either a line or groove in the nail plate distally.
The discharge of clear, sticky, mucoid material is typical of intermittent rupture of the false cyst. The diagnosis is usually made clinically, but the presence of a pseudocyst can be confirmed by high resolution MRI scanning of the affected digit.
Treatment is difficult and is frequently advocated by recurrence.
Under a digital block, the proximal nail fold can be reflected back, the cyst identified, and its communication with the synovium ligated. More proximal digital myxoid cysts can be treated by repetitive puncture and expression of the contents, injection of sclerosants, or surgery.
