A 44-year-old woman had a 13-year history of a small bulge of the left frontal region which had increased in size during the last year. At admission, an orange-sized, hard, fixed left frontal mass was found. Magnetic resonance imaging showed hyperostosis in the left frontal region which was causing a skull deformity and marked focal meningeal enhancement. A hyperostotic plaque meningioma was hypothesized. In-111 octreotide scintigraphy confirmed the diagnosis before surgery. In-111 octreotide scintigraphy allows biologic characterization of neoplasms in vivo.