Incidental Intense Orbital Uptake on [99 m Tc]Tc-HDP Bone Scintigraphy Revealing Spheno-Orbital En Plaque Meningioma: The Added Value of SPECT/CT and Multimodal Imaging

A 52-year-old woman underwent [99 m Tc]Tc-hydroxydiphosphonate ([99 m Tc]Tc-HDP) bone scintigraphy for evaluation of lower back pain. Whole-body imaging incidentally revealed intense uptake in the left orbital region, which was absent on a previous scintigraphy 8 years earlier. Skull single-photon emission computed tomography/computed tomography (SPECT/CT) proved to be essential in this setting, localizing the abnormal uptake to a hyperostotic reaction involving the greater wing of the sphenoid, with a characteristic spiculated appearance. These findings were highly suggestive of a spheno-orbital en plaque meningioma. Contrast-enhanced MRI demonstrated plaque-like dural thickening underlying the hyperostotic reaction, supporting the radiological diagnosis. The intense [99 m Tc]Tc-HDP uptake most likely reflected active osteoblastic/hyperostotic bone remodeling rather than uptake by the soft tissue tumor itself. This case illustrates the added value of SPECT/CT for localizing and characterizing unexpected skull-base uptake detected on planar bone scintigraphy. Conservative management with radiological follow-up was adopted.