Imaging Features of Dyke-Davidoff-Masson Syndrome

A 42-year-old male presented to the adult epilepsy clinic at Sultan Qaboos University Hospital, Muscat, Oman, in 2019 with right motor seizures accompanied by occasional generalisation and loss of consciousness, right-side hemiparesis and low intellectual capacity since early childhood. The patient had suffered a perinatal hypoxic ischemic injury due to a difficult delivery, which resulted in spastic cerebral palsy. His developmental history revealed delayed milestones and learning difficulties at school. His seizure episodes had increased in frequency over the years, requiring treatment with multiple antiepileptics. Despite being on four antiepileptic drugs, the patient continued to experience very frequent seizures. On examination, he had slurred speech and right facial deviation. He was able to walk without support, with a circumduction gait. There was right-sided spastic hemiparesis with brisk tendon reflexes and an extensor plantar response.

An electroencephalogram (EEG) was done and showed left hemispheric cerebral dysfunction with left hemispheric onset focal motor seizures. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain revealed atrophy of the left cerebral hemisphere with ipsilateral compensatory thickening of skull bones and hyperpneumatisation of the left frontal and sphenoidal sinuses.

A diagnosis of Dyke-Davidoff-Masson (DDM) syndrome was made based on clinical and radiological findings. The patient was managed with antiepileptic medications, muscle relaxants and physiotherapy. Due to his intractable seizures, he was offered surgical intervention at an outside facility.

The present case of DDM syndrome with characteristic clinical and radiological findings is a rare entity with few reported cases in literature. To the best of the authors’ knowledge, this is the first case to be reported from the current institution.

Informed patient consent for the purpose of publication was obtained.

Comment

DDM syndrome is a rare condition that was described for the first time in 1933 by Dyke, Davidoff and Masson.1,2 These researchers described the plain skull radiograph features of nine patients who presented with seizures, hemiparesis, facial asymmetry and mental retardation.1

There are two types of DDM syndrome (congenital and acquired).2 The congenital or infantile type presents early in infancy, secondary to previous intrauterine brain insults like vascular occlusion or anomaly of the middle cerebral artery mainly.2,3 The acquired type occurs later in childhood, secondary to variable causes affecting brain perfusion like infection, prolonged febrile seizure, trauma, haemorrhage or ischemia.2

The current patient presented with hemiplegia and seizures since childhood, which is likely due to the hypoxic ischemic injury that he sustained during the perinatal period. The classical imaging features of this condition are unilateral cerebral atrophy with ipsilateral calvarial thickening and hyperpneumatisation of the ipsilateral frontal sinus.1,3 Other reported findings are ipsilateral falcine displacement, elevation of the petrous ridge and wing of the sphenoid bone, atrophy of ipsilateral basal ganglia, brainstem and contralateral cerebellum and hyperpneumatisation of ipsilateral mastoid air cells.2

The current patient showed the classic clinical and imaging features described in the literature for DDM syndrome. The CT scan and MRI of the brain revealed unilateral left-sided cerebral atrophy with ipsilateral compensatory hypertrophic thickening of the skull bones [Figures 1 and 2]. The patient also showed hyperpneumatisation of the left frontal and sphenoidal sinuses and the left mastoid process. Atrophy of the ipsilateral thalamus and cerebral peduncle, flattening of the left anterior surface of the pons and medulla in keeping with Wallerian degeneration and contralateral cerebellar atrophy, were all present. The time-of-flight magnetic resonance angiogram revealed that the left middle cerebral artery and its branches were smaller compared to the right side [Figure 3]. It is noteworthy to mention that the imaging findings of cerebral hemiatrophy, features of Wallerian degeneration and crossed cerebellar diaschisis due to impaired neuronal connections can be seen after various major cerebral insults (commonly infarcts) at any time in life. However, the presence of skull and sinus hypertrophy is seen in insults that happen early in life, as classically described in DDM syndrome. The presence of the findings varies depending on the severity of the insults.

Figure 1.

Axial unenhanced CT scan of the brain with brain and bone windows showing (A) severe left-side cerebral atrophy with ex-vacuo dilatation of the ipsilateral lateral ventricle, (B) left-side compensatory calvarial hypertrophy (arrows) and (C) hyperpneumatisation and enlargement of the left frontal sinus (red arrow) and left mastoid air cells (yellow arrow).

Figure 2.

T2 weighted images showing (A) left thalamic atrophy (arrow) and (B) left cerebral peduncle atrophy (arrow) in the axial plane and (C) contralateral cerebellar atrophy (arrow) in the coronal plane, collectively demonstrating severe atrophy of the left cerebral hemisphere.

Figure 3.

A coronal image of the time-of-flight magnetic resonance angiogram showing the left middle cerebral artery and its branches, which are smaller than the those on the right side (arrow).

The most common differential diagnosis for this syndrome is chronic Rasmussen encephalitis, Sturge-Weber syndrome, basal ganglia germinoma and Fishman syndrome.1,2 However, the differentiation between them can be made by clinical and radiological findings. For example, chronic Rasmussen encephalitis is a rare progressive inflammatory disease affecting children who usually present with seizures and cognitive impairment. Imaging findings show unilateral cerebral atrophy without associated skull changes.1 Patients with Sturge-Weber syndrome usually present with seizures, intellectual disability and a typical port wine stain on the face in the distribution of the ophthalmic division of the trigeminal nerve. On imaging, the patient will show unilateral cerebral atrophy with increased angiomatosis and sometimes, ipsilateral cortical tram-track calcifications.2,3 DDM syndrome has a wide spectrum of presentation, ranging from mild symptoms to severely disabling symptoms.

Refractory seizures remain the most challenging complaint.4,5 Patients with refractory seizures may benefit from surgical interventions like functional hemispherectomy, with a reported success rate of 85% in selected cases.1,4 However, it is highly associated with long term adverse effects like obstructive hydrocephalus and chronic subdural hygromas.2,4 Hemispherotomy is another surgical option that is also effective and associated with fewer complications. Rehabilitation, physiotherapy, speech therapy and occupational therapy are important to improve the quality of life.4,5 The current patient was managed with antiepileptic medications, muscle relaxants and physiotherapy. Due to his intractable seizures, he was also offered surgical intervention at an outside facility.