GYNAECOLOGICAL AND OBSTETRIC IMAGING
|Year : 2004 | Volume
| Issue : 3 | Page : 267-268
|Thanatophoric dysplasia : Antenatal diagnosis
RB Dubey, YP Sachdev, S Adhav
Dept. of Radiodiagnosis, RMC Pravara Medical Trust, Lone-413736, India
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Keywords: Thanatophoric dysplasia, USG
|How to cite this article:|
Dubey R B, Sachdev Y P, Adhav S. Thanatophoric dysplasia : Antenatal diagnosis. Indian J Radiol Imaging 2004;14:267-8
|How to cite this URL:|
Dubey R B, Sachdev Y P, Adhav S. Thanatophoric dysplasia : Antenatal diagnosis. Indian J Radiol Imaging [serial online] 2004 [cited 2020 Sep 23];14:267-8. Available from: http://www.ijri.org/text.asp?2004/14/3/267/28600
| Case history|| |
A twenty- two years old female, second gravida, with second degree consanguinity marriage and history of 7 months amenorrhoea presented with loss of foetal movements since 2 days. There was no history of per vaginal bleeding, pain in abdomen, fever and vomiting. Her first baby had died on third day of life due to respiratory distress. On clinical examination the patient was haemodynamically stable. Uterus was relaxed with 22- 24 weeks size, however foetal heart sounds were not audible. On per vaginal examination cervix was undilated and uneffaced with internal os close. Obstetric ultrasonography was advised for further evaluation.
USG revealed a single dead intrauterine foetus in cephalic presentation. Placenta was anterior with grade II maturity. Liquor was adequate, showing internal echoes. Skull was deformed, hence BPD and HC were not measured.
There was shortening and bowing of long bones with FL measuring 18 mm corresponding to 15 weeks 1 day. AC was measuring 154 mm corresponding to 20 weeks 0 day.
Diagnosis suggested was thanatophoric dysplasia. The labour was induced and dead foetus delivered.
Kidigram of aborted macerated foetus revealed:
- Short and bowed humerii, femorii, forearm bones and tibiae with metaphyseal flaring and thorn like spurs from the metaphyseal ends.
- Absent fibula.
- Large head.
- Platyspondyly of lower lumbar vertebrae with H- shaped configuration.
- Bell shaped chest, short ribs and small scapulae.
- Decreased vertical height of iliac bones with increased horizontal width.
- Flat acetabulae.
- Small sacroiliatic notches.
| Discussion|| |
Thantophoric dysplasia has a reported incidence between 1/6000 and 1/17,000 births. There is no particularly predisposed population and recurrence risk is sporadic. It is due to new autosomal dominant mutation affecting different functional domains of FGFR 3 gene. There is disorder of endochondral ossification with decreased or absent chondrocytes that are disordered. The abnormal bone formation is result of abnormal mesenchyme like tissue in the growth plate and periosteum.
Two types have been described. Type I is more common, characterised by curved long bones and severe platyspondylyl.
Type II is characterised by straight although severely micromelic long bones, less severe platyspondylyl and usually a cloverleaf skull. This being a lethal dysplasia, stillbirth or death during neonatal life occurs due to respiratory failure.
The diagnosis is easily made in second trimester when mother presents with polyhydroamnios.
The sonographic criteria suggesting the diagnosis are(1):
Severe rhizomelic micromelia with bowing, limbs being less than third percentile for gestational age.
Hypoplastic thorax indicated by cardiac circumference greater than 60% of the thoracic circumference.
Normal abdomen appearing protuberant in comparison with hypoplastic thorax.
Skin appears thick sonographically due to extreme redundancy and may prevent normal movement and positioning of limbs, causing them to be oriented at right angles to the body.
Telephone receiver configuration of the long bones appear in utero similar to neonatal radiograph in type I.
Trilobed appearance of the skull in coronal view in type II.Temporal location of the bulging and bilaterality are clues to correct diagnosis.
Ventriculomegaly, agenesis of the corpus callosum, cardiac anomalies, renal anomalies and radioulnar synostosis are occasionally reported.
| Differential diagnosis|| |
Osteogenesis imperfecta type II- characterised by fractures of long bones.
Achondrogenesis- characterised by extreme hypomineralisation.
| Radiographic features are|| |
Large head as compared to skull base.
20 % of affected skull show cloverleaf skull due to primary craniosynostosis.
Narrow, bell- shaped with decreased anterior- posterior diameter.
Ribs are short, horizontal with flaring of the anterior ends.
Scapulae are small.
Long tubular bones:
Short, broad, curved with flaring of the metaphyses.
Telephone- like configuration of the femora.
Thorn- like projections from metaphyseal ends.
Thickening of soft tissues of the extremities.
Platyspondylyl and H or U configuration of the vertebrae on AP film due to normal size pedicles of the flattened vertebrae.
Height of the intervertebral disc spaces 3 to 4 times greater than adjacent vertebrae.
Decreased interpedunculate distance in the midlumbar region.
Decreased vertical height of iliac bones with increased horizontal width.
Small sacroiliatic notches.
Ischia and superior pubic ramii are well opacified.
| References|| |
|1.||Budorick N.E.The Foetal musculoskeltal ultrasound. In: Peter W. Callen, Ultrasonography in Obstetrics and Gynaecology 4th edition. W. B. Saunders,2000: 343- 345. |
|2.||Pritzker H. A, Murray R.O, et al.Congenital shortness of stature. In: The radiology of skeletal disorders. Vol. II. 3rd edition. Churchill Livingstone, 1990: 962 -963. |
R B Dubey
Dept. of Radiodiagnosis, RMC Pravara Medical Trust, Lone-413736
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2], [Figure - 3]
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