J Korean Med Sci.  2010 Jun;25(6):970-973. 10.3346/jkms.2010.25.6.970.

Absence of the Septum Pellucidum Associated with a Midline Fornical Nodule and Ventriculomegaly: A Report of Two Cases

• Chun YK
• Kim HS
• Hong SR
• Chi JG

• KMID: 2150883
• DOI: http://doi.org/10.3346/jkms.2010.25.6.970

Abstract

We report two autopsy cases that revealed the partial absence of the septum pellucidum with ventriculomegaly. In each case, the brain showed mild dilatation of both frontal horns of the lateral ventricles, normal third and fourth ventricles and no aqueductal stenosis. The posterior portion of the septum pellucidum was absent and the fornices were fused in a single midline nodule, abnormally displaced to a caudal position and lodged in the foramina of Monro. The brain base showed no apparent abnormalities; the optic nerves were well developed. We conclude that the caudally displaced fornix in the absence of the septum pellucidum may have intermittently obstructed the foramina of Monro and induced mild ventriculomegaly.

Keyword

Septum Pellucidum; Fornix, Brain; Hydrocephalus; Ventriculomegaly

Figure

• 

  Fig. 1 Coronal section of the Case 1 brain through the interventricular foramen. The lateral ventricles are mildly distended and the third ventricle is normal. A single midline fornical nodule (arrow) almost totally obstructs the foramina of Monro. The septum pellucidum is absent in its posterior portion and the corpus callosum seems normal.

• 

  Fig. 2 Gross findings of the brain of the Case 2. (A) Coronal section through the interventricular foramen. The frontal horns of the lateral ventricles are mildly distended with blunt angles. A single midline fornical nodule (arrow) obstructs the foramina of Monro. Wisps of the anterior part of the septum pellucidum are seen (arrow head). An iatrogenic tear of the corpus callosum is present. (B) The base of the brain shows well developed optic nerves (arrow), olfactory nerves and other cranial nerves. Gyri and sulci show no gross abnormalities.

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