Septo-optic dysplasia: Magnetic Resonance Imaging findings

Septo-optic dysplasia PLUS syndrome in a 23 years old patient: A case report

Septo-optic dysplasia (SOD) is a rare malformation defined by septum pellucidum abnormalities and hypoplasia of the optic nerves and chiasm. It can be associated with cortical development malformations such as schizencephaly, which is then called septo-optic dysplasia plus. It usually manifests at birth, although it may not be diagnosed until childhood, or rarely, adolescence. We report the case of a 23 years old patient, with a history of epilepsy since early childhood never labeled, which was diagnosed with SOD-PLUS with brain MRI in our department.

Review of the MRI brain findings of septo-optic dysplasia

AIM

To report the magnetic resonance imaging (MRI) findings from a retrospective case analysis of children with septo-optic dysplasia (SOD), a rare congenital disorder characterised by any combination of midline brain defects, optic nerve hypoplasia (ONH), and hypothalamic-pituitary dysfunction.

MATERIALS AND METHODS

SOD was defined radiologically as complete or partial septum pellucidum (SP) absence with hypoplasia of at least one of the optic nerves and/or chiasm. Local MRI databases were searched for SOD cases in children over an 18-year period, and studies reviewed by two consultant paediatric neuroradiologists. The extent of structural SP, optic nerve, chiasm, and hypothalamic-pituitary involvement was recorded, along with coexisting brain abnormalities.

RESULTS

Forty-eight cases of SOD were found; 44/48 (92%) demonstrated complete SP absence whereas 4/48 (8%) had partial absence. Eight of 48 cases (17%) exhibited unilateral ONH. Fifty-one percent of cases, where the pituitary was identified on MRI, demonstrated a structural pituitary abnormality, which included an ectopic posterior bright spot in 6%. The olfactory nerves were hypoplastic in 5/48 cases (10%). Twenty-seven of the 48 cases (56%) had another brain abnormality, resulting from some form of cortical formation abnormality/schizencephaly in 21/48 (44%).

CONCLUSION

A high rate of associated brain abnormalities was found in the present cohort, including structural pituitary abnormalities in 51% and cortical formation abnormalities/schizencephaly in 44%. This suggests there is not a single cause for SOD, rather SOD is the phenotypic end point from multiple aetiological events. Individual children with SOD may have coexisting intracranial abnormalities, and, hence, high-quality MRI is required in all.

Spotlight on the pediatric eye: a pictorial review of orbital anatomy and congenital orbital pathologies

Orbital lesions in the pediatric population vary from adults in terms of their presentation, unique pathology, and imaging characteristics. The prompt and accurate diagnosis of these lesions is imperative to prevent serious consequences in terms of visual impairment and disfigurement. Along with dedicated ophthalmologic examination, imaging is instrumental in characterizing these lesions, both for accurate diagnosis and subsequent management. In our pictorial essay, we provide a basic review of orbital embryology, anatomy, and congenital orbital pathologies, with emphasis on radiological findings.

Septo-optic dysplasia with cerebellar hemiagenesis

A 1-month-old girl child, who was found to have hydrocephalus on prenatal ultrasound, was postnatally evaluated with magnetic resonance imaging (MRI) of brain, which showed two classical findings of septo-optic dysplasia (SOD), namely optic nerve hypoplasia and absent septum pellucidum. In addition, the patient was found to have cerebellar hemiagenesis.

Septo-optic Dysplasia : Assessment of Associated Findings with Special Attention to the Olfactory Sulci and Tracts

PURPOSE

Septo-optic dysplasia is a congenital disorder consisting of optic nerve hypoplasia and absent septum pellucidum. While associated anomalies have been described, olfactory sulcus and bulb-tract hypoplasia have been scantily reported and was the focus of this study.

METHODS

The picture archival and communications system and radiology information system (PACS-RIS) was searched over 15 years for patients with suspected septo-optic dysplasia (n = 41) and cerebral magnetic resonance imaging (MRI). Included patients had coronal (≤3 mm), axial (≤4 mm), and sagittal (≤4 mm) imaging reviewed by two staff neuroradiologists by consensus. Both olfactory sulcus and bulb-tract hypoplasia were ascribed a grade of 0 (normal) to 3 (complete hypoplasia). Other associated congenital anomalies were recorded, if present. Incidence of anomalies were compared to age-matched and gender-matched control patients.

RESULTS

Out of 41 septo-optic dysplasia patients 33 were included (mean age = 120.7 months), with 8 excluded due to isolated septum pellucidum absence (n = 5), isolated bilateral optic hypoplasia (n = 2), or inadequate imaging (n = 1). An olfactory sulcus was hypoplastic on one or both sides in 14/33 (42.4%). Olfactory bulb hypoplasia was noted in one or both tracts in 15/33 (45.4%). A significant correlation was found between degree of olfactory sulcal and bulb-tract hypoplasia (ρ = 0.528, p = 0.0009). Other anomalies were: anterior falx dysplasia (n = 16, 48.5%), incomplete hippocampal inversion (n = 14, 42.4%), polymicrogyria (n = 11, 33.3%), callosal complete or partial agenesis (n = 10, 30.3%), schizencephaly (n = 8, 24.2%), ectopic posterior pituitary (n = 6, 18.2%), and nodular heterotopia (n = 4, 12.1%). Of the age-matched control patients 10/33 (30.3%) had at least mild anterior falx hypoplasia, and 1 control patient was noted to have unilateral incomplete hippocampal inversion (IHI); none of the age-matched control patients had olfactory sulcus or bulb-tract hypoplasia.

CONCLUSION

Olfactory sulcus and bulb-tract hypoplasia are fairly common in septo-optic dysplasia and can be discordant between sides. Of the other associated anomalies, anterior falx dysplasia seems to be the most common.