PMC5161676_01
Sagittal T1-weighted noncontrast (a) and axial T2-weighted (b) images at presentation through the sella demonstrate an abnormal heterogeneous intensity mass with confluent regions of T1 and T2 hypointensity centered within the sella with mild suprasellar extension. No osseous abnormality of the skull base is appreciated. The mass was presumed to be a pituitary adenoma.
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F1
She was referred for imaging at our institution, at which time an MRI of the brain revealed a 1.4 cm mass in the sella with suprasellar extension and impingement on the optic chiasm (Fig. 1). T1 and T2 hypointensity (Fig. 1) as well as trace foci of T1 hyperintensity possibly secondary to subacute blood products. There was no evidence of suspicious or abnormal marrow signal to suggest osseous involvement.
Images 1 month after presentation- Sagittal T1-weighted pre contrast image through the sella at the same slice selection as Figure 1 demonstrate marked interval growth of the sellar/suprasellar mass, which now abuts and elevates the optic chiasm (arrow). No osseous involvement or other intracranial abnormality is present.
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F2
Regularly scheduled MRI of the brain/sella obtained 4 weeks later demonstrated interval increase in size of the sellar/suprasellar mass (now 2.0 cm) (Fig. 2).
Sagittal (a) and coronal (b) T1-weighted post-contrast dedicated sellar images demonstrate heterogeneous hypoenhancement of the mass in comparison to compressed and displaced normal pituitary tissue (arrowhead). There is mass effect on the optic chiasm, and extension into the intercarotid space of the cavernous sinus on the left (arrow).
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F3
Postcontrast T1 weighted images demonstrated primarily hypoenhancing and nonehancing components (Fig. 3).
Coronal T2-weighted dedicated sella images demonstrating heterogeneous, primarily T2 hypointense signal in comparison to pituitary parenchyma, which is compressed and displaced to the right. (a) The tumor abuts the left cavernous and supraclinoid internal carotid arteries, as well as the bilateral A1 segments of the anterior cerebral arteries. (b) There is new subtle T2 hyperintensity in the left optic chiasm and nerve (arrow).
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F4
In addition, there was trace T2 hyperintensity suggestive of new edema in the left optic nerve (Figs. 4).
Axial bone window CT from the patient's whole body PET-CT at the level of the sellar/suprasellar mass demonstrates no evidence of osseous metastatic disease.
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F5
Whole body imaging with follow up PET CT was performed 3 days after the MRI brain/sella and demonstrated mild sellar FDG avidity but no evidence of additional abnormal hypermetabolic focus or osseous destruction on low mAS CT images (Fig. 5).
(a) Hematoxylin and eosin-stained section demonstrating a small round blue cell tumor (40X). (b) Membranous cytoplasmic immunoreactivity of tumor cells for CD 99 (hematoxylin counterstain, 40X). (c) Nuclear immunoreactivity of tumor cells for FLI-1 (hematoxylin counterstain, 40X).
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F6
Trans-sphenoidal biopsy of the mass was obtained, and histologic examination of the sellar mass disclosed a monomorphous small round blue cell tumor (Fig. 6a).