Azygous anterior cerebral artery with an anterior cranial fossa base meningioma.

Abstract

Sir, A 42‑year‑old lady presented with headache and anosmia of nine months duration. She had progressive loss of vision, and generalized seizures. She was conscious, but had a reduced attention span. Her visual acuity was limited to perception of hand movements close to face. Her magnetic resonance imaging (MRI) of the brain revealed a large meningioma arising from the olfactory groove, and extending until the tuberculum sella [Figure 1]. The magnetic resonance angiography showed lifting of both anterior cerebral arteries (ACA) with a single distal ACA (azygous ACA) [Figure 2]. A bifrontal craniotomy and a subfrontal approach facilitated excision of the tumor. The tumor was intimately related to both the ACAs and the distal azygous ACA. It was excised and a very small portion of the tumor was left at the junction of both ACAs at the site of critical perforators [Figure 3]. The postoperative period was uneventful. An azygous distal ACA is seen in 0‑5% of humans. [1] However, an azygous ACA commonly occurs in lower primates; hence, this anomaly is referred as a “monkey’s type” of ACA. [2,3] The azygous ACA may be associated with malformations like holoprosencephaly, agenesis of corpus callosum, meningoceles, lipoma, arachnoid cyst, and porencephalic cyst. [4‑7] In the available literature, the association of an azygous ACA with a coexisting suprasellar tumor has not been described. The association of an azygous ACA with an anterior cranial fossa meningioma, as seen in our patient, may be coincidental. It can, however, pose a significant challenge during surgery. Large meningiomas of anterior cranial fossa base may be adherent to the ACAs and surgery may lead to injury of this vessels. When there is a single ACA, as in our case, the injury to this vessel can cause infarction of both medial frontal lobes leading to paraplegia. Presence of a vascular anomaly in a close vicinity to the tumor calls for more precision during surgery.