Polysyndactyly

Case contributed by Lindsay Schwartz

Presentation

“Webbed” 4th and 5th toes on the right foot. Patient was born at full term.

Patient Data

Age: 2 days
Gender: Female
X-ray

Right foot: 

  1. The alignment and bone density is grossly normal on this nonweightbearing exam in this 2-day-old baby girl. 
  2. There are five metatarsals, and five ossified proximal phalanges. 
  3. There is fusion of the fourth and fifth toes, and an extra digit/ossification of the distal phalanx at the lateral side consistent with post-axial polydactyly with syndactyly. 
  4. The ossification center for the middle phalanx for the fifth toe and extra digit is not ossified at this time. 
  5. Radiographic follow-up in 6 months is suggested.

Left foot: 

  1. The alignment and bone density is normal. 
  2. No osseous anomaly is detected.

Case Discussion

This is a case of both polydactyly and syndactyly in a 2-day old baby girl. 

Polydactyly comes from the Greek roots "polus" (many) and "daktulos" (finger). It can be divided into pre-axial (located near the 1st digit), post-axial (located near the 5th digit) and central polydactyly (located within the central 3 digits), with post-axial being the most commonly found at roughly 1 per every 3000 live births.

Most cases of polydactyly are isolated, though some are associated with syndromes. Chromosomal trisomies, in particular, Trisomy 13 or Patau Syndrome can be associated with post-axial polydactyly. Other syndromic associations include VACTERL and the short rib polydactyly syndromes (SRPS) - a group of at least 5 rare, lethal ciliopathies causing severe osteochondrodysplasia. 

Syndactyly comes from the Greek roots “syn” (together) and "daktulos" (finger). It can be divided into simple (confined to the soft tissue) and complex (bone involvement) cases. It is estimated to occur in approximately 1 per 2500-5000 live births with a slight male preponderance. 2nd and 3rd digits tend to be more affected, and toes may be affected slightly more often than fingers. 

Though most cases are isolated (and are either sporadic or familial), some can be associated with syndromes. Triplodies (i.e. 69 XXX), VACTERL, and acrocephalosyndactyly or acrocephalopolysyndactyly syndromes (i.e. Apert, Crouzon syndrome) can be associated with syndactyly. 

Radiologists play an important in the diagnosis of both polydactyly and syndactyly. Assessment of the anatomy of both the normal and abnormal digits for surgical planning and to rule out additional skeletal anomalies that would make syndromic associations more likely is vital for the appropriate management of all cases.

This case was submitted with supervision and input from:

Soni C. Chawla, M.D.
Associate Professor
Department of Radiological Sciences
David Geffen School of Medicine at UCLA
Olive View - UCLA Medical Center   

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Case information

rID: 57404
Published: 23rd Dec 2017
Last edited: 13th Dec 2019
Inclusion in quiz mode: Included
Institution: Olive View - UCLA Medical Center

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