Vascular malformation within the flexor tendon sheath

We report an unusual location of a capillary vascular malformation found entirely within the flexor tendon sheath of an 8-year-old girl. Vascular malformations have been found in many locations throughout the hand but have, to our knowledge, not been reported to involve the vinculum of the flexor tendon sheath. The vascular malformation was contained completely within the sheath. Therapeutic management involved surgical excision of the vascular malformation.