Experience with 5-aminolevulinic Acid in fluorescence-guided resection of a deep sylvian meningioma

Abstract

The 5-aminolevulinic acid (5-ALA)-induced tumor fluorescence is a useful intraoperative marker for the diagnosis and the detection of various malignancies, but its use in meningioma is only reported infrequently. In meningioma, a complete resection of the tumor mass is crucial for the prevention of recurrence and postoperative morbidities. Deep sylvian meningioma is a rare type of meningioma where complete tumor removal is complicated by its deep anatomical location and close involvement with the middle cerebral artery. From our experience, 5-ALA-mediated fluorescence facilitated a safe excision whilst preserving critical neurovascular structures. To our best knowledge, this is first report from use of 5-ALA in a deep sylvian meningioma.

Keywords: 5-aminolevulinic acid; Deep sylvian meningioma; Meningioma without dural attachment; Resection.

Fig. 1

A preoperative non-contrast enhanced axial CT (A) shows an area of high density in the left temporal lobe, most likely a calcification. An axial T2-weighted magnetic resonance (MR) image without contrast (B) shows a mass lesion of mixed signal intensity with edema located deep in the left Sylvian fissure. It displays heterogeneous contrast enhancement on a T1-weighted MR image (C). A post-operative axial T2-weighted MR image taken within 48 hours of the surgery (D) shows the resection cavity with a residual tumor tissue strongly adherent to the middle cerebral artery.

Fig. 2

An intra-operative photograph of the excised mass shone under the white light (A) is taken using the surgical microscope. Under the violet-blue excitation light (B), it exhibits strong red fluorescence, confirming the presence of a neoplasm.

Fig. 3

Pathological examination confirms the diagnosis of the fluorescent mass as a meningioma. Microscopically, the tissue demonstrates syncytial growth of meningothelial cells with bland looking nuclei and psammoma bodies (H&E stain; original magnification ×200).