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 Table of Contents  
Year : 2021  |  Volume : 9  |  Issue : 2  |  Page : 353-354

Posterior quadrantic dysplasia: An unusual cause of focal seizures

1 Department of Neurology, MOSC Medical College, Kolenchery, Kochi, Kerala, India
2 Department of Radiology, MOSC Medical College, Kolenchery, Kochi, Kerala, India

Date of Submission06-Jul-2021
Date of Decision06-Sep-2021
Date of Acceptance09-Sep-2021
Date of Web Publication29-Dec-2021

Correspondence Address:
Dr. Krishnan Balagopal
Department of Neurology, MOSC Medical College, Kolenchery, Kochi, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/amhs.amhs_156_21

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Hemimegalencephaly (HME) is one of the rare malformations of cortical development that can present in children and in adults with refractory seizures. One of the localized forms of HME is posterior quadrantic dysplasia (PQD). This entity commonly involves hypertrophy of the parieto-temporo-occipital lobes with periventricular signal changes on imaging. Presentation is with focal seizures in children and in adults. We present here a 24-year-old man presenting with recurrent left focal seizures who was found to have PQD on imaging. He was started on anticonvulsants with improvement in his symptoms. This report aims to highlight the characteristic imaging findings and clinical features of PQD.

Keywords: Focal seizures, hemimegalencephaly, posterior quadrantic dysplasia

How to cite this article:
Balagopal K, Nadarajah J, Thottiyil JJ. Posterior quadrantic dysplasia: An unusual cause of focal seizures. Arch Med Health Sci 2021;9:353-4

How to cite this URL:
Balagopal K, Nadarajah J, Thottiyil JJ. Posterior quadrantic dysplasia: An unusual cause of focal seizures. Arch Med Health Sci [serial online] 2021 [cited 2022 Aug 19];9:353-4. Available from: https://www.amhsjournal.org/text.asp?2021/9/2/353/334000

  Introduction Top

Hemimegalencephaly (HME) is one of the rare congenital malformations of cortical development seen in clinical practice. The main features of HME are enlarged and dysplastic overgrowth of one or all parts of a cerebral hemisphere.[1] HME usually affects the entire hemisphere but localized forms have also been reported in the literature.[2] One of the types seen is posterior quadrantic dysplasia (PQD) or hemi-HME with an enlargement of the parieto-occipito-temporal lobe, sparing the frontal lobe of a single hemisphere.[3] Most patients who have PQD on imaging show dysmorphic ipsilateral occipital horn with high-signal posterior periventricular white matter and abnormal gyri with heterotopias.[4] We present here a case of a 24-year-old patient with recurrent episodes of left focal seizures who was detected to have PQD on imaging.

  Report Top

A 24-year-old patient with no prior comorbidities or significant history presented with a history of recurrent episodes of seizures over the past 2 years. These episodes were associated with sudden loss of awareness, involuntary posturing of left upper limb followed by fall to the ground, and loss of consciousness for around 5 min. Clinical examination revealed no focal deficits while laboratory values were within normal limits. Magnetic resonance imaging of the brain showed marked enlargement of the right parieto-temporo-occipital lobe and periventricular astrogliosis, sparing of frontal lobes, and polymicrogyria with blurred cortical-white matter junction that was consistent with a diagnosis of PQD [Figure 1] and [Figure 2]. The patient was subjected to an electroencephalogram which showed intermittent spike and slow-wave discharges from the right parieto-occipital regions. He was started on Levetiracetam and Clobazam at therapeutic doses. At follow-up, his seizures were under control and he was doing well on medications.
Figure 1: (a) Magnetic resonance imaging T1-weighted image at the level of the pons shows focal posterior quadrantic dysplasia involving the parieto-occipital lobe on the right side (white thin straight arrow). (b) Axial T2-weighted image at the level of the thalamus shows focal megalencephaly of the right parietal lobe (thin straight arrow) and sparing of frontal lobes (white thick short arrows)

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Figure 2: Noncontrast axial TI-weighted fat-saturated images at the level of the thalamus (a) and coronal fluid-attenuated inversion recovery (b) show periventricular hyperintensity adjacent to the occipital horn of the right lateral ventricle (white arrows)

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  Discussion Top

PQD or hemi-HME is one of the malformations of cortical development which is a rare cause of focal seizures in children and adults. It is a sporadic cortical development malformation that involves the posterior three lobes of a single hemisphere and spares the frontal cortex. PQD is a rare condition, accounting for only 3% of cortical dysplasia diagnosed by imaging.[2] Most common presentation is infantile spasms. Mental retardation, axial hypotonia, and mild contralateral hemiparesis are seen in older children. Many of the cases are refractory to anticonvulsants and may require surgical management.[5] Early diagnosis and availability of motor-sparing neurosurgical disconnective procedures have led to dramatically reduced mortality and morbidity rates, apart from gifting the affected children a better quality of life.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


The authors wish to thank their friends and family.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Feidert A. Hemi-hemimegalencephaly or posterior quadrantic dysplasia, a rare cause of focal epilepsy in an otherwise healthy young woman: A case report. Cureus 2020;12:e10002.  Back to cited text no. 1
Ikeda KM, Mirsattari SM. Evolution of epilepsy in hemimegalencephaly from infancy to adulthood: Case report and review of the literature. Epilepsy Behav Case Rep 2017;7:45-8.  Back to cited text no. 2
D'Agostino MD, Bastos A, Piras C, Bernasconi A, Grisar T, Tsur VG, et al. Posterior quadrantic dysplasia or hemi-hemimegalencephaly: A characteristic brain malformation. Neurology 2004;62:2214-20.  Back to cited text no. 3
Kumar I, Aggarwal P, Rai T, Gupta V. Posterior quadrantic dysplasia with localized hemimegalencephaly in a patient with giant congenital melanocytic nevus: First case report. Neuroradiol J 2019;32:210-4.  Back to cited text no. 4
Guerrini R, Dobyns WB. Malformations of cortical development: Clinical features and genetic causes. Lancet Neurol 2014;13:710-26.  Back to cited text no. 5


  [Figure 1], [Figure 2]


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