Dyke-Davidoff-Masson syndrome (DDMS), also known as Dyke-Davidoff-Masson syndrome, is a rare neurological condition characterized by unilateral cerebral hemiatrophy (or hypoplasia) of one brain hemisphere. This results from an insult to the developing brain, typically during the fetal period or early childhood, and is accompanied by compensatory changes in the skull and sinuses on the same side, along with contralateral neurological deficits.10

It was first described in 1933 by Dyke, Davidoff, and Masson based on skull X-ray and pneumoencephalographic findings in patients with infantile hemiplegia.

Types and Etiology

DDMS is divided into two main types:

• Congenital (infantile): Due to prenatal or perinatal brain injury, such as infections, vascular occlusions (e.g., involving the middle cerebral artery or other arterial anomalies, including rare posterior cerebral artery hypoplasia), unilateral cerebral circulation anomalies, or other gestational issues. Symptoms often appear in the perinatal period or infancy.
• Acquired: Results from postnatal insults in early childhood, including trauma, tumors, infections (e.g., encephalitis), ischemia, hemorrhage, or prolonged febrile seizures.1

The underlying mechanism involves neuronal loss and impaired brain growth on the affected side, leading to atrophy. Vascular causes reducing cerebral blood flow are commonly implicated in congenital cases. Left hemisphere involvement and male predominance are frequently noted (though it can affect either side or gender).12

Clinical Presentation

Symptoms vary depending on the extent and timing of the brain injury. Common features include:

• Seizures (often the most prominent symptom; can be refractory): Generalized tonic-clonic, focal (impaired awareness, motor), or other types.
• Contralateral hemiparesis or hemiplegia (weakness on the opposite side of the body; seen in ~70% of cases).
• Facial asymmetry or limb asymmetry.
• Intellectual disability or learning difficulties (~46% of cases).
• Developmental delays (motor, speech/language disorders).
• Other possible findings: Gait issues, rapid deep tendon reflexes, facial paralysis (less common), and rarely sensory loss or psychiatric manifestations.

Onset can range from infancy to adulthood, with mean age around 19 years in reviewed cases. Prognosis for seizure control and function depends on severity and early management.42

Radiological Features

Diagnosis relies heavily on characteristic imaging findings, which reflect the hemiatrophy and compensatory skull changes:

• Cerebral hemiatrophy: Reduced volume of one hemisphere, prominent ipsilateral sulci, and dilatation of the ipsilateral lateral ventricle.
• Skull changes (ipsilateral/compensatory): Thickening of the calvarium (skull vault), hyperpneumatization (enlargement) of paranasal sinuses (especially frontal, but also ethmoid and sphenoid), and mastoid air cells.
• Additional signs: Elevation of the petrous ridge and sphenoid wing, ipsilateral falcine shift, possible middle fossa hypoplasia, or Wallerian degeneration in the brainstem/mesencephalon.
• Modality preferences: CT best shows bony changes (calvarial thickening, sinus enlargement). MRI provides detailed brain parenchymal assessment (atrophy, sulcal prominence, ventricular enlargement) and may show associated vascular anomalies.

These features distinguish DDMS from other causes of hemiatrophy.40

Here are representative imaging examples from reported cases:

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(Images typically show axial/coronal views with arrows highlighting hemiatrophy, ventricular dilatation, sulcal prominence, and calvarial/sinus changes on the affected side.)

Differential Diagnosis

Conditions to consider include:

• Sturge-Weber syndrome (often with port-wine stain).
• Rasmussen encephalitis (progressive, usually without prominent calvarial changes).
• Hemimegalencephaly (enlarged hemisphere).
• Other rare syndromes like Silver-Russell or Fishman syndrome.

Management and Prognosis

There is no curative treatment; management is symptomatic and multidisciplinary:

• Antiepileptic drugs for seizure control (may be refractory; some cases require optimized regimens).
• Physiotherapy and occupational therapy for hemiparesis and motor deficits.
• Speech therapy for language issues.
• Support for intellectual/developmental needs (special education, etc.).
• In select refractory cases, surgical options like hemispherectomy may be considered, though this is not first-line.

Outcome varies: Many patients achieve reasonable seizure control and functional independence with early intervention, but significant disability can persist in severe cases. Further research is needed due to the rarity and variability of the condition.42

Note: This is general medical information based on published literature. DDMS requires evaluation by a neurologist with appropriate imaging (CT/MRI) for diagnosis. If this relates to a specific patient (e.g., yourself or someone under your care as a physician), consult a specialist for personalized assessment, as individual cases differ widely.