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Case 1. (A) Coronal T1 magnetic resonance imaging (MRI) and (B) coronal CT in bone window show the mass with hyperostotic bone formation with erosion through the adjacent skull base and lamina papyracea. (C) Coronal postcontrast fat-saturated T1 MRI shows the avidly, homogenously enhancing recurrent mass involving the skull base and right medial rectus muscle.
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Computed tomography (CT) and magnetic resonance imaging (MRI) imaging identified a sinonasal mass in the right frontal recess with extension into the ethmoids, intimately associated with the lamina papyracea with hyperostotic bone formation (Fig. 1A, B). She recovered well, without morbidity, but recurred 17 months later with an avidly enhancing mass involving the anterior skull base and right medial rectus (Fig. 1C).
Case 1. (A) Low-power (4 x ) hematoxylin and eosin (H&E) stain shows the highly cellular lesion expanding the sinus submucosa. (B) High-power (40 x ) H&E stain shows the highly cellular but fairly bland and monotonous spindle cell neoplasm in a herringbone or fascicular pattern. (C) Intermediate power (10 x ) shows patchy positive staining in the lesional cells for smooth muscle actin. (D) Intermediate power (10 x ) shows patchy positive staining in the lesional cells for neural marker S100.
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Surgical pathology showed a mucosal lesion comprising bland spindle cells without mitosis, necrosis, or pleomorphism, but the neoplastic proliferation was infiltrative into bone (Fig. 2).
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Case 2. (A,B) Sagittal and (C) axial postcontrast computed tomography images show the frontal sinus mass with hyperostotic bone formation and erosion through the superior orbital wall into the orbit and through the posterior table of the skull base with intracranial extension.
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It also extended inferiorly into the ethmoids, eroded the lamina papyracea, contacted the left medial rectus, and eroded the superior orbital wall (Fig. 3).
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Case 3. (A) Sagittal postcontrast computed tomography scan and (B) coronal postcontrast fat-saturated T1 magnetic resonance imaging images show the left sinonasal mass centered in the ethmoid cells with avid homogeneous enhancement and extension through the lamina papyracea and anterior skull base.
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CT and MRI imaging showed a T1-enhancing, T2 hypointense mass with hyperostotic bone formation of the left ethmoid sinuses that has eroded through the adjacent lamina papyracea and anterior skull base and contacted the medial rectus and the dura (Fig. 4).