Absent Septum Pellucidum

[ksmall]

I had an MRI done in 2005 for a study at the NIH. I was a healthy volunteer. They sent me the results (which were strange) but never explained them in detail.

Findings:
"The septum pellucidum is absent. Squaring off of the posterior margin of the genu of the corpus callosum suggests that rather than congenital absence of the septum pellucidum, this may actually represent a ruptured cavum septum pellucidum and cavum vergae. Other than this abnormality, the ventricular system is not abnormally prominent. Reformatting of the images into the coronal plane does not suggest abnormalities of the optic nerves, chiasm, or tracts. There is minimal interdigitation of the frontal lobes, suggesting that the anterior falx cerebri may be fenestrated or partially absent. The cerebellar tonsils project 2mm below the inferior margin of the foramen magnum, without crowding of structures.

There is mucosal thickening in the right frontal sinus. The mastoid air cells are clear. The orbits and their contents are grossly unremarkable. Normal intravascular flow voids are seen in the major intracranial vessels.

Impression:
Congenital absence of the septum pellucidum, versus rupture of a cavum septum pellucidum and cavum vergae."


Since finding these papers in a recent move I have done a little research and from what I can find this is rare and usually associated with other major defects of the brain and eyes. Can you maybe explain my MRI to me?

Thanks.

[Lama Chahine, MD]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.

Without the ability to examine you and obtain a history and review your MRI, I can not tell you what the exact implications of your MRI findings. However I will try to provide you with some useful information.

You are correct in stating that abnormalities of the septum pellucidum including absence of it could be associated with other malformations, such as eye and brain malformations. The septum pellucidum is a membrane that occurs in the midline of the brain. Children born without a septum pellucidum often have associated abnormalities of the optic nerve (nerve to the eye) and pituitary gland (a gland also in the midline of the brain, responsible for the production of various hormones). It is caused by mutations in specific genes in some cases. In general, the extent of manifestations are variable, the person can be entirely normal without any neurologic deficits, while others could have motor and cognitive developmental delay. Absence of a septum pellucidum can therefore occur in someone who is otherwise entirely normal individuals; it may be entirely clinically insignificant, especially if detected incidentally in adulthood, which it sounds like occurred in your case. However, in other cases, subtle abnormalities, such as vision problems due to optic nerve involvement can occur.

Contacting the study coordinators that recruited you for the MRI may be helpful in obtaining more information; another option would be evaluation by a neurologist and perhaps neuro-opthalmologist should optic nerve problems be suspected.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.