Pontomedullary disconnection: fetal and neonatal considerations

Abstract

The cerebellar and pontocerebellar hypoplasias present a unique challenge when detected in the developing fetus. A diverse aetiology and prognosis make counselling of these families difficult. Advances in fetal imaging allow for more accurate diagnosis and counselling, but postnatal MRI is still required. A case is presented in which cerebellar hypoplasia was detected at 20 weeks gestation. Later fetal imaging provided further information, but a diagnosis of pontomedullary disconnection was not made until the postnatal MRI scan. The clinical findings and possible causes of such pontocerebellar abnormalities are discussed.

A developmental classification of malformations of the brainstem

“…As a result, they do not appear in this study. We also did not encounter any cases of brainstem disconnection syndrome, a disorder in which a segment of the midbrain or pons is nearly completely absent, with the more rostral and caudal portions of the brainstem being connected by only a thin strand of white matter 60–63. The few reports of this entity suggest potential genetic or destructive causes 61…”

Brainstem Disconnection: Case Report and Review of the Literature

“…In case 5 as well as in our case the cerebellar hypoplasia could be already detected at 25 weeks of gestation. MacCann et al performed a fetal MRI, which confi rmed the cerebellar hypoplasia and revealed a pontine hypoplasia, but failed to show the disconnection [4] . We use the general term brainstem disconnection.…”

Magnetic resonance imaging of the fetus

“…Pontine hypoplasia and a ‘kinked brainstem’ (Fig. 10) may be seen with MRI, but more detailed visualization of the brainstem is more difficult 67 . In a recent retrospective review concentrating on fetal posterior fossa abnormalities there was complete agreement between fetal and postnatal MRI in only 59% of cases.…”

“…10) may be seen with MRI, but more detailed visualization of the brainstem is more difficult. 67 In a recent retrospective review concentrating on fetal posterior fossa abnormalities there was complete agreement between fetal and postnatal MRI in only 59% of cases. In 15%, the postnatal scan excluded the fetal MRI diagnosis, and, in 26%, additional anomalies were revealed.…”