CLOVERLEAF SKULL (KLEEBLATTSCHADEL SKULL)

• Premature closure of coronal and lambdoid sutures. Wide variation in initial detection of craniostenosis. Usually well developed by 19-22 weeks but there are reports of the deformity not evident until the third trimester.
• Bulging of the temporal bones and confluence of the anterior and posterior fontanelles.
• Expansion of the anterior cranial fossa superiorly.
• Expansion of middle cranial fossa laterally forming two bulges.

ETIOLOGY

• Defective development of the cranial bones with secondary synostosis.
• A primary development disorder of the brain with secondary deformation of the skull.

ASSOCIATED ANOMALIES

1. Amniotic band syndrome
2. Antley-Bixler syndrome
3. Apert syndrome
4. Beare-Stevenson syndrome (cutis gyratum; acanthosis nigrans; hypertelorism; cleft palate; bifid scrotum; carniosynostosis with / without cloverleaf skull).
5. Campomelic dysplasia
6. Carpenter syndrome
7. Crouzon syndrome
8. Partial trisomy 13q syndrome.
9. Partial trisomy 15q syndrome.
10. Pfeiffer syndrome
11. Say-Poznanski syndrome (short wide clavicles; winged scapulae; rib anomalies with prominent costovertebral junctions; wide ischial separation; angulated ulnae; polydactyly of the hands and feet; abnormal metacarpals and metatarsals).
12. Shpprintzen-Goldberg syndrome (marfanoid phenotype and craniosynostosis).
13. Thanatophoric dysplasia type 2
14. COH syndrome (craniosynostosis, ocular hypotelorism, thumb duplication, small 5th finger, micropenis, bifid scrotum).
15. IWK syndrome (craniosynostosis, broad hands and feet).
16. Osteoglophonic dysplasia (craniosyostosis, lucent metaphyseal defects brachydactyly, dwarfism).
17. Micromelic bone dysplasia with cloverleaf skull and straight femora).
18. Isolated cloverleaf skull.
19. Iatrogenic – postbilateral subtemporal decompression for hydrocephalus/

.

CLASSIFICATION

Classification - 3 types (Partington et. al. 1971.)

• Type 1 - Cloverleaf skull co-exists with Thanatophoric Dwarf.
• Most common and severe type.
• Hydrocephalus (very common). Obstruction distal to the 4th ventricle from hypoplasia of the chondrocranium with a basilar deformity.
• Facial anomalies
• exopthalmos.
• hypertelorism.
• downward displaced ears.
• flat nasal root.
• high forehead.
• mid- facial hypoplasia.
• Type 2 - Cloverleaf skull associated with less severe skeletal lesions.
• joint ankylosis.
• subluxation of radial heads.
• Type 3 - Isolated Cloverleaf skull.
• Best prognosis.

DIFFERENTIAL DIAGNOSIS

  Frequently misinterpreted as an encephalocele or hygroma.

REFERENCES

1. Weiner CP, Williamson RA, Bonsib SM. Sonographic Diagnosis of Cloverleaf Skull and Thanatophoric Dysplasia in the Second Trimester. J Clin Ultrasound 1986, 14: 463-465.
2. Stamm ER, Pretorius DH, Rumack CM, Manco-Johnson ML. Kleeblattschadel Anomaly. In utero sonographic appearance. J Ultrasound Med 1987, 6: 319-324.
3. Bernstein PS, Gross SJ, Cohen DJ et.al. Prenatal diagnosis of type 2 Pfeiffer syndrome. Ultrasound Obstet Gynecol 1996;8:425-428