Case report of a novel nonsyndromic unilateral syndactyly of the hand

Syndactyly is a cutaneous and/or bony digital malformation with possible webbing of adjacent fingers or toes and uni- or bilateral occurrence. We report an 84-year old woman with a novel non-syndromic congenital malformation of her left hand. Clinical examination showed that she only had four digits. Radiograph of the hand revealed synostosis of the second and third proximal phalanx, resulting in a triangular shaped bone with relatively normal articulations at both ends. The phalangeal base of the fused finger tapers distally and is broader than the middle phalangeal bases of the ring and little finger. This malformation does not fit in any of the known types of syndromic or non-syndromic syndactylies. Our case report highlights that radiological imaging is crucial for identification of bony syndactyly and correct classification of a given syndactyly. Knowledge of the different types of syndactylies is important because certain malformations may occur as a defining part of a syndromic disease.