PMC4138817_01
(a,b) T1 and T2 MRI sequences revealing a left-sided heterogeneously enhancing lesion adjacent to the cerebral peduncle. (c) CT angiogram revealed no evidence of aneurysm malformation
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F1
Initial cerebral magnetic resonance imaging (MRI) demonstrated an 8 mm oval lesion in the anterior left interpeduncular cistern that was hyperintense on T1 and heterogeneous on T2-weighted images [Figure 1a and b]. On the computed tomography angiography (CTA), the lesion enhanced but did not correspond to an intracranial aneurysm [Figure 1c].
(a) Gradient echo MRI revealing round hypointense lesion with ferromagnetic susceptibility signals. (b) CISS MRI sequence revealing a left-sided heterogeneously enhancing lesion
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F2
A second MRI showed ferromagnetic susceptibility signals on gradient echo images [Figure 2a]. T2-weighted sequences better delineated the lesion and its relation to the oculomotor nerve [Figure 2b]. The suspected diagnosis was CA of the third cranial nerve.
(a) Intraoperative image disclosing a raspberry-like lesion arising within the left oculomotor nerve in the interpeduncular cistern. (b,c) Postresection image revealing the decompressed third nerve with preservation of nerve continuity despite its deformity (arrow head) and the intact contralateral oculomotor nerve (long arrow). (d) Postoperative CT scan showing gross total resection
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F3
Through a left subtemporal approach, exposure of the interpeduncular cistern revealed a raspberry-like lesion bulging from the third cranial nerve, anterolateral to the left cerebral peduncle [Figure 3a]. A well delineated plane of dissection allowed removal of the lesion while preserving the integrity of the nerve [Figure 3b and c]. Postoperative computed tomography (CT) scan showed no complication [Figure 3d].
(a-c) H and E stain showing tightly packed vascular channels with no intervening nervous tissue containing thrombotic and blood products with varying thickness of hyalinized endothelial walls lacking smooth muscle or elastic tissue
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F4
Histopathological analysis showed a lesion with high vascularity and hyalinized channels lined by a single layer of endothelial cells, findings that confirmed the diagnosis of a cavernous angioma [Figure 4].