Investigation of a cyclopic, human, term fetus by use of magnetic resonance imaging (MRI)

Sirenomelia: An anatomical assessment and genetic sex determination of two cases

The etiology of sirenomelia is currently unknown. Data are limited in comparing external and internal abnormalities using modern imaging technologies and molecular genetic analysis. The purpose of the current study was designed to compare external and internal anatomical defects in two cases of sirenomelia and Potter's sequence. Considered rare, Potter's sequence is a fetal disorder with characteristic features of bilateral renal agenesis, obstructive uropathy, atypical facial appearance, and limb malformations. The internal and external malformations of two term fetuses with sirenomelia and Potter's sequence were compared using assessment of external features, radiography and MRI on internal structures, and molecular genetic studies on sex determination. Data reveal that both fetuses were male and manifested with an overlapping but distinct spectrum of abnormalities. Principal differences were noted in the development of the ears, brain, urogenital system, lower limbs, pelvis, and vertebral column. Defects of the axial mesoderm are likely to underlie the abnormalities seen in both fetuses. The first one, which had only caudal defects, was found to have a spectrum of abnormalities most similar to those associated with more severe forms of the small pelvic outlet syndrome, although the structure and orientation of the sacrum and iliae were different from previously reported cases. The other had both caudal and cranial defects, and was most similar to those described in the axial mesodermal dysplasia syndrome. Defects associated with sirenomelia can be evaluated with standard gross anatomy examination, radiology, MRI, and modified PCR techniques to determine anatomical abnormalities and the sex of preserved specimens, respectively. Evidence indicated that sirenomelia could be developed via various etiologies.

A probable case of holoprosencephaly with cyclopia in a full-term fetus from a modern skeletal collection

OBJECTIVE

This study presents evidence of a probable case of holoprosencephaly with cyclopia, which has been rarely reported in the paleopathological literature.

MATERIALS

The skeletal remains of a male fetus between 36 and 40 gestational weeks from the Collezione Antropologica LABANOF (CAL) Milano Cemetery Skeletal Collection were studied.

METHODS

The bones were macroscopically examined, and pathological anomalies were recorded and evaluated alongside paleopathological and clinical literature.

RESULTS

Developmental anomalies were observed. In particular, a single orbit and optical canal were present, and the frontal, sphenoid and palatine bones were prematurely fused. These changes altered the normal morphology of the midline structures of the cranium and face.

CONCLUSIONS

The developmental anomalies observed are consistent with a case of holoprosencephaly associated with cyclopia.

SIGNIFICANCE

Holoprosencephaly is a fatal congenital condition caused by the failure of the prosencephalon to separate in two halves. This condition is clinically well-known, with an estimated modern incidence of 1/16,000 births; however, the paleopathological literature lacks reports that would help anthropologists and paleopathologists interpret these anomalous signs on dry bone. This report documents a rare paleopathological case of the condition on a full-term fetus from a modern skeletal collection.

LIMITATIONS

Taphonomic and anthropic factors may have impaired the observation of all pathological features.

SUGGESTIONS FOR FURTHER RESEARCH

Comparative studies with cases from documented collections could improve knowledge of the appearance of this condition on dry bones.

An osteological assessment of cyclopia by micro-CT scanning

PURPOSE

Imaging modalities such as micro-CT scanning and three-dimensional reconstruction are providing a mechanism for detailed analysis of skeletal components not only of normal specimens but also through revisitation of the abnormal. The aim of this study was to analyse the craniofacial skeleton of five human fetuses with cyclopia by means of micro-CT scanning and three-dimensional reconstruction.

MATERIALS AND METHODS

The study consisted of five cyclopean individuals from the paediatric collection of the School of Anatomical Sciences, University of the Witwatersrand. The specimens ranged in age from 22 to 42 weeks of gestation. The osteological features of each bone of the skull were analysed with the aid of micro-CT scanning and analysis using VG studiomax software.

RESULTS

A detailed analysis of all the bones of the skull revealed that the upper two-thirds of the viscerocranium and the anterior region of the basicranium were the most affected regions of the cyclopean fetuses. The ethmoid, nasal, inferior concha and the lacrimal bones were absent in all the cases of cyclopia. Major abnormalities were found in the premaxillary region which affected the development of the anterior dentition.

CONCLUSION

This study supports the suggestion that the malformations of the visceral bones are secondary to defective development of the presphenoid and mesethmoid cartilages. The ethmoidal bones are important midline struts during normal development and their absence in cyclopia leads to non-laterality of facial features.

Ethmocephaly with amniotic band syndrome

Ethmocephaly is the rarest form of holoprosencephaly, which occurs due to an incomplete cleavage of the forebrain. Clinically, the disease presents with a proboscis, hypotelorism, microphthalmos and malformed ears. Amniotic band syndrome is another rare congenital malformation with ring-like constriction bands in the limbs, head, face or trunk. We present a case of ethmocephaly with amniotic band syndrome, which is likely the first of its kind, published in the literature.

New classification scheme of proboscis lateralis based on a review of 50 cases

BACKGROUND

Among congenital nasal deformities, proboscis lateralis is one of the rarest. Boo-Chai classified proboscis lateralis into four groups. Recently, we encountered a new case of proboscis lateralis with median cleft lip. We noticed that this classification had not been considered according to convalescence and embryologics, and further refinement seemed to be needed.

METHODS

We reviewed all cases of proboscis lateralis reported in English through 2009 and classified them by intercanthal distance.

RESULTS

A total of 34 studies involving 50 cases were reviewed. Six cases were identified as having normal intercanthal distance. Three of them presented nose abnormalities and fit Boo-Chai group II category. The other three were consistent with group I. Hypertelorism was observed in 27 cases and was further divided into two groups based on the occurrence of a frontal encephalocele. Seventeen cases without a frontal encephalocele were compatible with Boo-Chai groups III and IV. The other 10 cases associated with a visible encephalocele had encephalopathy; most died at an early age, and long-term survival cases suffered developmental delay and mental retardation. Seventeen cases were defined as hypotelorism, and all cases also presented as holoprosencephaly.

CONCLUSIONS

The redefined classification contains two new groups: group V as hypertelorism with encephalocele and group VI as hypotelorism. A new classification scheme is proposed as not only convenient for clinical application but also embryologically accurate.

Ethmocephaly caused by de novo translocation 18;21--prenatal diagnosis

Ethmocephaly is a rare anomaly associated with partial failure of cleavage of the prosencephalon. Morphologically, it is closely related to cyclopia. We present an extremely rare case of ethmocephaly diagnosed in utero and caused by an unbalanced de novo translocation 18;21.