Samii, Farhoudi, Andalib, Moskowitz, Burnstock, Gjedde, Vafaei

Bilateral Transverse Sinus Hypoplasia: A Rare Case Report

Elyar Sadeghi-Hokmabadia, Masoud Poureisab, Neda Ghaemiana*, Zahra Parsianc

aNeurosciences Research Center, Tabriz University of Medical Science, Tabriz, Iran
bDepartment of Radiology, Radiotherapy and Nuclear Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
cDepartment of Emergency Medicine, Tabriz University of Medical Sciences, Tabriz, Iran

Neda Ghaemian, Neurosciences Research Center, Tabriz University of Medical Science, Tabriz, Iran.Tel/Fax: +98-41-333340730 Email:

Received: 2017-06-10
Accepted: 2017-12-12

© 2018 Swedish Science Pioneers, All rights reserved.


The dural sinuses are pathways for drainage of blood from brain to the internal jugular veins. Occipital sinus is a rare normal anatomical variation of dural sinuses which acts as an alternative drainage pathway when the transverse sinuses are hypoplastic. It drains blood from skull and brain to the internal jugular vein. The variations can culminate in wrong diagnosis and imaging interpretation. We reported a 33 years old pregnant woman presented with headache and normal neurological examination. Magnetic resonance imaging and magnetic resonance venography studies revealed occipital sinus as the main drainage pathway of the brain. Both the transverse sinuses were hypoplastic. Without considering this rare variation such conditions can culminate in wrong diagnosis, which can be prevented by reporting such rare conditions.

Keywords Transverse sinus, Hypoplasia, Headache


The dural sinuses are pathways for drainage of blood from brain to the internal jugular veins [1]. Cerebral venous sinuses have anatomic variations [2]. Occipital sinus is the smallest dural venous sinus, lies on the inner surface of the occipital bone at the attaching site of the falx cerebri to the skull, which connects both the sigmoid sinuses and internal vertebral plexus [1, 3]. Occasionally, it is difficult to diagnose sinus thrombosis owing to non-specificity of clinical presentation and variability of venous sinuses anatomy. The variations can culminate in wrong diagnosis [4]. Incorrect imaging interpretation may also result from anatomic variations [3].

Case Presentation

A 33 years old pregnant woman gravid 2/para 0/abortus 1, at 8 weeks of gestation presented with acute onset headache, which started 3 days ago, the pain was more in the parietal-occipital region and did not radiate to anywhere. The patient’s headache was throbbing and constant without diurnal pattern, and was neither aggravated nor alleviated with physical activity, or any other factor. Nausea and vomiting were the accompanying symptoms. Pain did not respond to oral analgesics. She had a history of chronic generalized deep seated and throbbing headaches.

On admission she was afebrile with a blood pressure of 120/80 mmHg. General and neurological examinations were normal. Ophthalmoscopy did not show signs of increased intracranial pressure. She underwent brain magnetic resonance (MR) imaging andbrain MR venogram (MRV) (Figure 1). At MRV both transverse and sigmoid sinuses are hypo plastic,with bilateral dominant occipital sinuses.With hydration and anti-migraine treatment she was completely symptom free on the 3rd day.


Figure 1: Brain MRV, anterior-posterior (a) and lateral (b) views show absence of normal transverse sinus with dominant occipital sinus. (a and b) show normal appearing transverse sinus for comparison.Superior sagittal sinus (blue arrows), transvers sinus (red arrows), sigmoid sinus (white arrows), jugular vein (green arrows), occipital sinus (yellow arrows).


Previous studies have reported the presence of occipital sinuses in a range from 4 to 35.5% of cases [3].

Widjaja found a relationship between size of the transverse sinus and the presence of occipital sinus in children [5]. Occipital sinuses can be the main drainage pathways of the intracranial veins instead of the transverse or sigmoid sinuses when these sinuses are hypoplastic or aplastic [6].

Unilateral hypoplasia of transverse sinus with dominant occipital sinus is not uncommon but this is a rare case of bilateral transverse sinus hypoplasia with bilateral dominant occipital sinuses. Physicians should be aware of such anatomical variations and must not misdiagnose it as cerebral venous sinuses thrombosis (CVST) especially when there are risk factors for CVST like pregnancy in this case.


Rare anatomic variations of dural sinuses should be considered while interpreting brain MRI and MRV. Misdiagnosis of this condition as cerebral venous sinuses thrombosis can culminate in dire consequences of anticoagulant treatment, all of which can be avoided by familiarity with this variation.


1. Goyal G, Singh R, Bansal N, Paliwal VK: Anatomical Variations of Cerebral MR Venography: Is Gender Matter? Neurointervention 2016, 11(2):92-98.

2. Lydiatt DD, Ogren FP, Lydiatt WM, Hahn, FJ: Increased intracranial pressure as a complication of unilateral radical neck dissection in a patient with congenital absence of the transverse sinus. Head Neck 1991, 13:359–362.

3. Tubbs RS1, Bosmia AN, Shoja MM, Loukas M, Curé JK, Cohen-Gadol AA: The oblique occipital sinus: a review of anatomy and imaging characteristics. SurgRadiol Anat. 2011, 33(9):747-749.

4. Alper F, Kantarci M, Dane S, Gumustekin K, Onbas O, Durur I, Importance of Anatomical Asymmetries of Transverse Sinuses: An MR Venographic Study. Cerebrovasc Dis 2004, 18:236-239

5. Widjaja E and Griffiths PD: Intracranial MR Venography in Children: Normal Anatomy and Variations. American Journal of Neuroradiology 2004, 25 (9) 1557-1562.

6. Dora F, Zileli T: Common variations of the lateral and occipital sinuses at the confluenssinuum. Neuroradiology1980, 20(1):23-27.


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