PMC6744806_01
CT head without contrast demonstrates a hyperdense left frontal mass with the erosion of the inner table of the frontal sinus, near midline.
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F1
A head computed tomography (CT) was obtained and demonstrated a large, hyperdense left frontal extra- axial mass along the floor of the anterior cranial fossa, with bony erosion into the frontal sinus [Figure 1].
MRI brain. (a) T1 noncontrast and (b) T1 postcontrast sequences demonstrate a 7.0 cmx5.0 cmx4.9 cm heterogeneously enhancing left frontal mass with T1 shortening at the posterior aspect of the lesion, suggestive of prior hemorrhage. (c) T1 postcontrast sequences also reveal a dural tail and (d) T2-weighted sequences demonstrate a partial cerebrospinal fluid cleft around the periphery of the lesion; both findings suggest that the mass is extra- axial in origin.
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F2
T1 shortening, suggestive of prior hemorrhage, and subacute blood products posterior to the tumor margin, abutting the frontal horn of the left lateral ventricle. T1 postcontrast imaging revealed a dural tail and T2-weighted images demonstrated a partial cerebrospinal fluid cleft around the periphery of the lesion; both findings suggested that the mass was extra-axial in origin [Figure 2].
CT abdomen/pelvis demonstrates a hypodense hepatic lesion (arrow) concerning for metastatic disease.
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F3
The CT scans revealed multiple small, hypodense liver lesions concerning for metastases [Figure 3] as well as pulmonary emboli.
(a) Histologic sections of the left frontal mass demonstrate a high-grade SFT/HPC. Note the four mitotic figures in the mid-upper right (red arrows). (H & E, 200x). (b) Nuclei of the neoplastic cells express STAT6, indicating a fusion of the NAB2 and STAT6 genes (Diaminobenzidine, 100x).
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F4
III). Immunoperoxidase stains demonstrated nuclear expression of STAT6 by many of the neoplastic cells indicating fusion of the NAB2 and STAT6 genes [Figure 4].
(a) Metastatic hemangiopericytoma in liver core biopsy (H & E, 200x). (b) Expression of STAT6 by the neoplastic cells (Diaminobenzidine, 100x).
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F5
Histologic sections revealed neoplastic cells that were morphologically similar to those in the intracranial tumor specimen and immunohistochemistry confirmed the NAB2/STAT6 fusion [Figure 5].
Postoperative surveillance MRI brain (T1 postcontrast) demonstrates no evidence of residual or recurrent disease.
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F6
MRIs of the brain and abdomen were obtained following the completion of radiation treatment. MRIs of the brain remained stable, with no evidence of disease recurrence at 18 months postoperatively [Figure 6].