Thalidomide-induced Phocomelia

General Considerations

• From about 1957-1961, Thalidomide found use in Europe, Japan, Australia and Canada as an anti-emetic during pregnancy until it was found to be a teratogen causing birth defects
• It is estimated that 10,000 babies were born with defects before the drug was banned worldwide
  • It is also estimated that 40% died of birth defects
• Fetuses were found to be vulnerable to upper limb phocomelia between days 27-30 of gestation and only a single dose of the drug could produce defects
• In the USA, the drug had not been approved by the FDA
  • In 1962, US Congress enacted new requirements for testing the safety of drugs during pregnancy
• Subsequently, the drug has been approved for use in multiple myeloma and the treatment of leprosy and may be helpful in the treatment of AIDS
• Phocomelia refers to short or absent long bones with the hands extending in a  “flipper-like” form
  • Thalidomide also caused
• Absence of the radial ray (radius and thumb)
• Malformations of the eyes, ears, heart, kidneys and nervous system

Clinical Findings

• Effects of drug were usually bilateral, especially in upper extremity
• Upper extremities were more affected than lower
• The upper extremity bones affected are, in order:
  • Thumbs (complete absence is most frequent)
• Radius (may be short and bowed)
• Humerus (like radius, is affected from distal to proximal)
• Ulna
• Fingers 3, 4 and 5

Imaging Findings

• There are 3 types of phocomelia of the upper extremity
  • Hand attaches to the shoulder (forearm and arm deficient)
• Forearm attaches to the shoulder (arm deficient)
• Hand attaches to the arm (forearm deficient)

Differential Diagnosis

• Sporadic phocomelia
• Holt-Oram syndrome
• Thrombocytopenia Absent Radius Syndrome (TAR syndrome)

Associated defects

• Microphthalmos
• Coloborna
• Intestinal atresia
• Absent or deformed pinna
• Renal malformations
• Congenital cardiac disease

Thalidomide-induced Phocomelia. Single views of both upper extremities in a patient known to have been exposed to Thalidomide in-utero shows deformities of the forearm with fusion at the elbow and absence of fingers on the right (white arrow) and absence of the radius, fusion of the elbow and shortening of the ulna with absence of fingers on the left (yellow arrow).
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