The Neuroradiology Journal 19: 606-608, 2006
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Isolated Unilateral Cerebellar Hypoplasia A Case Report
P. GUPTA, S. HEDGIRE, T. KALYANPUR, JAYESH SR, B. MADHAVRAM, N. SEKHAR, ILAYARAJA V, D. RAJA, P. MEHTA, M. CHERIAN Kovai Medical Center and Hospital Coimbatore; Tamil Nadu, India
Key words: cerebellar hypoplasia, unilateral, cerebellar malformations.
SUMMARY – Isolated cerebellar malformations are relatively rare CNS anomalies, when they do occur they are frequently symptomatic. Some cases of asymptomatic cerebellar malformations have been reported. Unilateral cerebellar hypoplasia is one such entity. We describe a case of unilateral cerebellar hypoplasia presenting with non-specific neurological complaints.
Introduction Cerebellar malformations frequently occur along with other CNS anomalies, but are seldom isolated. The traditional classification system for categorizing anomalies featuring cerebellar hypogenesis divides them into total or subtotal agenesis, lateral aplasia, median aplasia and hypoplasias which may be total, lateral or medial. This classification however is not useful for radiologists or clinicians in that it is descriptive but lacks any underlying embryologic or pathophysiologic basis. Case Report A 39-year-old healthy man presented to the Neurology OPD with a history of recurrent mild headaches since the age of five, he had no other complaints. His neurological examination was unremarkable. There was no history of cerebrovascular episodes and no known history of any perinatal events. The patient underwent a CT scan which showed the absence of the inferior part of the right cerebellar hemisphere and a posterior fossa CSF collection (figure 1). A normal fourth ventricle and lack of mass effect excluded the diagnoses of a porencephalic cyst and posterior fossa arachnoid cyst respectively. 606
Subsequently he underwent an MR scan which confirmed the findings seen on the CT. The MR scan also showed the vermis to be intact (figure 2), the cerebral hemispheres were normal (figure 3). There was no evidence of dysplasia. The pons, medulla and midbrain were normal. The contralateral cerebellar hemisphere was normal. The adjacent calvarium displayed no abnormality. Discussion A descriptive classification proposed by Patel and Barkovich broadly segregates cerebellar malformations into cerebellar hypoplasias and dysplasias 1. There is however a poor correlation between the severity of the deformity and the clinical syndrome 2. This classification does aid in identifying the primary anomaly when the appearance of the cerebellum is unusual and the cause unknown 2. Cerebellar hypoplasias may be focal or generalized and are associated with inborn errors of metabolism, congenital infections or gross congenital anomalies 2. Unilateral cerebellar hypoplasia typically does not present with cerebellar signs or symptoms 3 but may be associated with psychomotor symptomatology 4. Analysing the imaging findings of 70 patients, Patel and Barkovich 1 found no notable difference between the cerebella of patients with large fourth ventricle cysts (Dandy-
Isolated Unilateral Cerebellar Hypoplasia. A Case Report
Figure 1 Axial plain CT scan showing absent right cerebellar hemisphere and posterior fossa CSF collection.
P. Gupta
Figure 2 Axial T1-weighted image showing intact vermis.
Figure 3 Coronal T2-weighted image showing normal cerebral hemispheres.
Walker malformations) and those without large fourth ventricle cysts (isolated cerebellar hypoplasia); isolated cerebellar hypoplasia was found in two children and one adult. The two children had undergone evaluation for developmental delay and the adult for persistent headaches. All three patients had mild ataxia but were otherwise neurologically normal. The exact etiology of this disorder is unknown but some au-
thors have suggested a vascular or traumatic etiology of probable early intrauterine origin 4,5. This hypothesis has been supported by antenatal ultrasound findings 6. But there has been a case reported to become symptomatic late in adult life with a possible vascular trigger 7. There has also been a report of an association with ipsilateral vertebral artery hypoplasia 8, but our case was not available for investigation with angiography. 607
Isolated Unilateral Cerebellar Hypoplasia. A Case Report
Our case illustrates the absence of neurologic signs/symptoms commensurate with morphologic abnormality of the cerebellum and ermphasizes the need to examine the embryologi-
P. Gupta
cal basis and molecular biology of the entity. Collated imaging and clinical data may help further understanding of these anomalies in future.
References 1 Patel S, Barkovich AJ: Analysis and Classification of Cerebellar Malformations. Am J Neuroradiol 23: 10741087, 2002. 2 Barkovich AJ: Congenital Malformations of the Brain and Skull. Barkovich AJ, eds. Pediatric Neuroimaging. 3rd ed. Philadelphia: Lippincott Williams & Wilkins 2000: 251-381. 3 Boltshauser E, Steinlin M, Martin E et Al: Unilateral cerebellar aplasia. Neuropediatrics Feb 27: 50-3, 1996. 4 Granados-Alzamora V, Pascual-Pascual SI, PascualCastroviejo I: Unilateral Cerebellar Hypoplasia: an Alteration of Vascular Origin? Rev Neurol 36: 841-5, 2003. 5 Mancini J, Lethel V, Hugonenq C et Al: Brain injuries in early foetal life: consequences for brain development. Dev Med Child Neurol 43: 52-5, 2001. 6 Robins JB, Mason GC, Watters J et Al: Case report: Cerebellar Hemi-Hypoplasia: Prenat Diagn 18: 173-7, 1998.
608
7 Franco E, Casado JL, Diaz-Espejo C et Al: Late Symptomatic Initiation of Unilateral Cerebellar Hypoplasia: Neurologia 15: 261-3, 2000. 8 Simon M, Kafritsas D: Unilateral Cerebellar Hypoplasia: Clin Neuropathol 11: 71-3, 1992.
Dr Prashant Gupta, MBBS Department Radiology Kovai Medical Center and Hospital Coimbatore Avinashi Road Coimbatore - Tamil Nadu 641014 INDIA E-mail: [email protected]
www. centauro. it
Isolated Unilateral Cerebellar Hypoplasia A Case Report
P. GUPTA, S. HEDGIRE, T. KALYANPUR, JAYESH SR, B. MADHAVRAM, N. SEKHAR, ILAYARAJA V, D. RAJA, P. MEHTA, M. CHERIAN Kovai Medical Center and Hospital Coimbatore; Tamil Nadu, India
Key words: cerebellar hypoplasia, unilateral, cerebellar malformations.
SUMMARY – Isolated cerebellar malformations are relatively rare CNS anomalies, when they do occur they are frequently symptomatic. Some cases of asymptomatic cerebellar malformations have been reported. Unilateral cerebellar hypoplasia is one such entity. We describe a case of unilateral cerebellar hypoplasia presenting with non-specific neurological complaints.
Introduction Cerebellar malformations frequently occur along with other CNS anomalies, but are seldom isolated. The traditional classification system for categorizing anomalies featuring cerebellar hypogenesis divides them into total or subtotal agenesis, lateral aplasia, median aplasia and hypoplasias which may be total, lateral or medial. This classification however is not useful for radiologists or clinicians in that it is descriptive but lacks any underlying embryologic or pathophysiologic basis. Case Report A 39-year-old healthy man presented to the Neurology OPD with a history of recurrent mild headaches since the age of five, he had no other complaints. His neurological examination was unremarkable. There was no history of cerebrovascular episodes and no known history of any perinatal events. The patient underwent a CT scan which showed the absence of the inferior part of the right cerebellar hemisphere and a posterior fossa CSF collection (figure 1). A normal fourth ventricle and lack of mass effect excluded the diagnoses of a porencephalic cyst and posterior fossa arachnoid cyst respectively. 606
Subsequently he underwent an MR scan which confirmed the findings seen on the CT. The MR scan also showed the vermis to be intact (figure 2), the cerebral hemispheres were normal (figure 3). There was no evidence of dysplasia. The pons, medulla and midbrain were normal. The contralateral cerebellar hemisphere was normal. The adjacent calvarium displayed no abnormality. Discussion A descriptive classification proposed by Patel and Barkovich broadly segregates cerebellar malformations into cerebellar hypoplasias and dysplasias 1. There is however a poor correlation between the severity of the deformity and the clinical syndrome 2. This classification does aid in identifying the primary anomaly when the appearance of the cerebellum is unusual and the cause unknown 2. Cerebellar hypoplasias may be focal or generalized and are associated with inborn errors of metabolism, congenital infections or gross congenital anomalies 2. Unilateral cerebellar hypoplasia typically does not present with cerebellar signs or symptoms 3 but may be associated with psychomotor symptomatology 4. Analysing the imaging findings of 70 patients, Patel and Barkovich 1 found no notable difference between the cerebella of patients with large fourth ventricle cysts (Dandy-
Isolated Unilateral Cerebellar Hypoplasia. A Case Report
Figure 1 Axial plain CT scan showing absent right cerebellar hemisphere and posterior fossa CSF collection.
P. Gupta
Figure 2 Axial T1-weighted image showing intact vermis.
Figure 3 Coronal T2-weighted image showing normal cerebral hemispheres.
Walker malformations) and those without large fourth ventricle cysts (isolated cerebellar hypoplasia); isolated cerebellar hypoplasia was found in two children and one adult. The two children had undergone evaluation for developmental delay and the adult for persistent headaches. All three patients had mild ataxia but were otherwise neurologically normal. The exact etiology of this disorder is unknown but some au-
thors have suggested a vascular or traumatic etiology of probable early intrauterine origin 4,5. This hypothesis has been supported by antenatal ultrasound findings 6. But there has been a case reported to become symptomatic late in adult life with a possible vascular trigger 7. There has also been a report of an association with ipsilateral vertebral artery hypoplasia 8, but our case was not available for investigation with angiography. 607
Isolated Unilateral Cerebellar Hypoplasia. A Case Report
Our case illustrates the absence of neurologic signs/symptoms commensurate with morphologic abnormality of the cerebellum and ermphasizes the need to examine the embryologi-
P. Gupta
cal basis and molecular biology of the entity. Collated imaging and clinical data may help further understanding of these anomalies in future.
References 1 Patel S, Barkovich AJ: Analysis and Classification of Cerebellar Malformations. Am J Neuroradiol 23: 10741087, 2002. 2 Barkovich AJ: Congenital Malformations of the Brain and Skull. Barkovich AJ, eds. Pediatric Neuroimaging. 3rd ed. Philadelphia: Lippincott Williams & Wilkins 2000: 251-381. 3 Boltshauser E, Steinlin M, Martin E et Al: Unilateral cerebellar aplasia. Neuropediatrics Feb 27: 50-3, 1996. 4 Granados-Alzamora V, Pascual-Pascual SI, PascualCastroviejo I: Unilateral Cerebellar Hypoplasia: an Alteration of Vascular Origin? Rev Neurol 36: 841-5, 2003. 5 Mancini J, Lethel V, Hugonenq C et Al: Brain injuries in early foetal life: consequences for brain development. Dev Med Child Neurol 43: 52-5, 2001. 6 Robins JB, Mason GC, Watters J et Al: Case report: Cerebellar Hemi-Hypoplasia: Prenat Diagn 18: 173-7, 1998.
608
7 Franco E, Casado JL, Diaz-Espejo C et Al: Late Symptomatic Initiation of Unilateral Cerebellar Hypoplasia: Neurologia 15: 261-3, 2000. 8 Simon M, Kafritsas D: Unilateral Cerebellar Hypoplasia: Clin Neuropathol 11: 71-3, 1992.
Dr Prashant Gupta, MBBS Department Radiology Kovai Medical Center and Hospital Coimbatore Avinashi Road Coimbatore - Tamil Nadu 641014 INDIA E-mail: [email protected]
