|Year : 2021 | Volume
| Issue : 3 | Page : 183-185
Bilateral persistent primitive olfactory artery incidentally detected by computed tomography angiography and digital subtraction angiography: An extremely rare case report
Anshu Mahajan, Apratim Chatterjee, Gaurav Goel
Department of Neurosciences, Medanta - The Medicity, Gurgaon, Haryana, India
|Date of Submission||07-Aug-2020|
|Date of Acceptance||19-Aug-2021|
|Date of Web Publication||23-Sep-2021|
Dr. Gaurav Goel
Department of Neurosciences, Medanta - The Medicity, Gurgaon, Haryana
Source of Support: None, Conflict of Interest: None
We present a rare case of bilateral persistent primitive olfactory artery incidentally detected on computed tomography angiography and digital subtraction angiography in a 53-year-old female with symptomatic left-sided tight internal carotid artery stenosis. This imaging finding can be useful to the literature.
Keywords: Anterior cerebral artery, internal carotid artery, persistent primitive olfactory artery
|How to cite this article:|
Mahajan A, Chatterjee A, Goel G. Bilateral persistent primitive olfactory artery incidentally detected by computed tomography angiography and digital subtraction angiography: An extremely rare case report. J Anat Soc India 2021;70:183-5
|How to cite this URL:|
Mahajan A, Chatterjee A, Goel G. Bilateral persistent primitive olfactory artery incidentally detected by computed tomography angiography and digital subtraction angiography: An extremely rare case report. J Anat Soc India [serial online] 2021 [cited 2021 Dec 3];70:183-5. Available from: https://www.jasi.org.in/text.asp?2021/70/3/183/326421
| Introduction|| |
Persistent primitive olfactory artery (PPOA) is an extremely rare anomaly of anterior cerebral artery (ACA), in which the anomalous artery courses anteroinferomedially along the ipsilateral olfactory tract and makes a hairpin to turn posterior to the olfactory bulb to continue as A2 segment of ACA. The clinical significance of this anomaly is its association with cerebral aneurysm. It is also very important for the neurosurgeon to recognize this anomaly before performing the surgery at the anterior skull base to avoid any catastrophic complication. We present a rare case of bilateral PPOA incidentally detected on computed tomography angiography (CTA) and digital subtraction angiography (DSA) in a patient with symptomatic left internal carotid artery (ICA) tight stenosis who was treated with left carotid stenting.
| Case Report|| |
A 53-year-old hypertensive female presented with a history of two episodes of transient right-sided weakness for 1 month which recovered completely. Noncontrast computed tomography head was normal and CTA of brain and neck vessels showed >90% stenosis of left carotid bulb and an incidental anomalous course of bilateral ACAs [Figure 1]a. We performed magnetic resonance imaging (MRI) brain which showed small microvascular ischemic changes in brain parenchyma however no fresh infarct. We planned carotid stenting for her symptoms. Successful left carotid stenting was done and DSA (Axiom Artis Zee; Siemens, Erlangen, Germany) of cerebral vessels showed incidental anomalous anteroinferior course of bilateral ACA which then turns posteriorly and superiorly to continue as A2 segment of ACAs suggestive of PPOA [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e. Detailed review of angiography was done which showed no evidence of associated aneurysm in our case.
|Figure 1: Computed tomography angiography (lateral projection) showed A1 segment of the both anterior cerebral artery courses anteroinferiorly, makes a hairpin turn (arrow), and connects posterosuperiorly to the A2 segment of the anterior cerebral artery, indicative of a persistent primitive olfactory artery (a). Right internal carotid artery injection (posteroanterior and lateral projection) showed right Persistent primitive olfactory artery (arrow) (b and c). (d and e) Left common carotid artery injection (posteroanterior and lateral projection) showed left persistent primitive olfactory artery (arrow)|
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| Discussion|| |
At around 4–5.7 mm embryo length, cranial and caudal divisions of ICA are formed. Cranial division of the ICA is termed as PPOA. Anterior choroidal artery and middle cerebral artery branches off from the primitive olfactory artery (POA). As the embryo reaches 11.5–18 mm length, there are two branches from the POA, the original one is to the nasal fossa and other one represents the future continuation of the ACA. Later in the end of the stage, the opposite artery joins with its fellow by the plexiform anastomosis which then forms the future anterior communicating artery (ACoA). The original POA forms an anastomosis with the ACA and later POA regress in size and the two arteries, medial striate and recurrent artery of Heubner are formed from the POA and ACA anastomosis. The recurrent artery of Heubner is not the remnant of the POA. PPOA results when ACA arises from the distal portion of the POA and the proximal portion keeps its course along the olfactory bulb. Thus, the PPOA had typical morphology of hair pin loop as normal distal part of ACA is located posterosuperiorly.,, There are three main types of PPOA [Figure 2]. Type 1 arises from the ICA and has a course along the olfactory tract and makes a hair pin turn to supply the distal ACA territory. It is usually associated with absence of ACoA. Type 2 arises from the ACA enters the nasal cavity through the cribriform plate as the ethmoidal artery. Type 3 is a type between variants 1 and 2 described by Horie et al.'s group. This anomalous artery has two branches, anterior branch anastomosis with ethmoidal artery and superior branch forms callosomarginal branch of the ACA. Variation supplying the distal MCA territory has also been reported in literature.,, In our case, it was type 1 PPOA which arises from the ICA and courses anteroinferiorly, makes a hairpin turn and then connects posterosuperiorly to the distal ACA. Type 1 PPOA has high incidence of aneurysm formation particularly at the hairpin bend region probably due to increased hemodynamic stress at this location which was not found in our index case. Although, follow-up imaging was advised in our patient to monitor for aneurysm formation. There are many reports of single cases or retrospective studies about the PPOA in the literature.,,,,, However, there is a paucity of literature about the reports of bilateral PPOA which is extremely rare anomaly. Till date, there are five reported cases of bilateral PPOA in the literature. Takeshita et al. Nozaki et al. reported a case of bilateral PPOA on cerebral angiography. Retrospective study by Uchino et al. described 1 case of bilateral PPOA on MRI and Kwon et al. described three cases of bilateral PPOA on MRA and CTA in their retrospective study. Most of the cases of PPOA in the literature have been reported from Japan, Korea, and Serbia.,,,,,,,, To our knowledge, ours is the first case reported from India which was incidentally detected bilateral PPOA demonstrated on CTA and DSA.
|Figure 2: Drawing showing 3 types persistent primitive olfactory artery (orange colour). Type 1 makes hair pin loop (arrow) to supply the distal anterior cerebral artery territory (a). Type 2 anastomose with ethmoidal artery (b). Type 3 has two branches, anterior branch anastomosis with ethmoidal artery and superior branch forms callosomarginal branch of the anterior cerebral artery (c)|
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Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]