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Year : 1999  |  Volume : 9  |  Issue : 2  |  Page : 85-86
Pseudocyst of the germinal matrix

Department of Radiodiagnosis, Christian Medical College & Hospital, Vellore, Tamil Nadu, India

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How to cite this article:
John BA, Shayamkumar N K, Murthy R. Pseudocyst of the germinal matrix. Indian J Radiol Imaging 1999;9:85-6

How to cite this URL:
John BA, Shayamkumar N K, Murthy R. Pseudocyst of the germinal matrix. Indian J Radiol Imaging [serial online] 1999 [cited 2021 Feb 26];9:85-6. Available from:

Pseudocysts of the germinal matrix (PGM) are an occasional finding and are detected by cerebral ultrasound in pre-term and full-term newborns [1]. Cavitations within the germinal matrix are defined as pseudocysts because they are not lined by epithelium [2]. We would like to report a case of PGM cyst in a one month old infant.

A one month old baby who developed seizures was brought for a cerebral US examination. The baby was born by vaginal delivery in a private nursing home. The cord was present around the neck during birth. The baby did not cry at birth and had a poor APGAR score. The sucking reflex was poor and the baby developed multifocal seizures six hours after birth. A diagnosis of hypoxic-ischemic encephalopathy was made. The ultrasound examination revealed a five millimeter cyst at the caudo-thalamic notch between the head of the caudate and the thalamus [Figure - 1],[Figure - 2]. The rest of the brain parenchyma and the ventricular system were normal.

Pseudocysts of the germinal matrix (PGM) can be present at birth in both pre-term and full-term infants. They frequently occur following hemorrhage, but may follow a variety of intra-uterine insults including infectious diseases (cytomegalovirus, rubella), ischemia or small vascular insults [2]. Most PGM cysts are detected at the head of the caudate nucleus (caudo-thalamic notch) or more medially near the foramen of Monro [4]. In our patient, the cyst was located at the caudo-thalamic notch. The PGM cyst in our patient must have most probably developed due to ischemia.

The germinal matrix begins in the first trimester as a zone of cellular proliferation from which neuronal and glial cells originate. It lines the entire ventricular system, but regresses and disappears in time as migration is completed. One of the last regions to regress lies near the venous angle of the lateral ventricles in a zone referred to as the caudo-thalamic groove. It is this location that is the most common site of origin of intracranial hemorrhage in the premature infant [3].

The precise frequency of PGM cysts diagnosed with ultrasound is difficult to estimate because the few large studies performed have been based on selected and differing populations of newborn infants. In these reports, the estimated frequency varies from one to five percent [4]. PGM cysts are infrequently detected in the neonatal population and are usually not associated with neuro-developmental complications in the absence of other abnormalities [4]. Recent reports confirm that isolated PGM cysts are likely to be benign in otherwise healthy full-term infants [5].

   References Top

1.Levene MI. Diagnosis of subependymal pseudocyst with cerebral ultrasound. Lancet 1980; 2: 210.   Back to cited text no. 1  [PUBMED]  
2.Mito T ando Y, Takeshita K, et al . Ultrasonographical and morphological examination of subependymal cystic lesions in maturely born infants. Neuropediatrics 1989; 20: 211.   Back to cited text no. 2    
3.Diane SB. Cranial sonography of the infant. In: William SB Jr, ed. Pediatric Neuroradiology, 1st ed. Philadelphia: Lippincott-Raven, 1997: 37-68.   Back to cited text no. 3    
4.Luca AR, Sergio D, Lorenzo Q, et al : Prenatal pseudocysts of the germinal matrix in preterm infants. J Clin Ultrasound 1997; 25: 169-173.   Back to cited text no. 4    
5.Larcos G, Grueewald SM, Lui K. Neonatal subependymal cysts detected by sonography: prevalence, sonographic findings and clinical significance. AJR 1994; 162: 953-956.   Back to cited text no. 5    

Correspondence Address:
Bobby A John
Department of Radiodiagnosis, Christian Medical College & Hospital, Vellore, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

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[Figure - 1], [Figure - 2]


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