Harbor-UCLA Neuro-Radiology Case Conference

Sahar Farzin, M.D.Department of Radiology, Harbor UCLA Medical Center

Thu Tran, M.D.Department of Pathology, Harbor UCLA Medical Center

History: 62 year old male presents with headache, nausea and vomiting

Imaging

Axial head CT with contrast

Imaging

Axial T1WIs post-gadolineum

Imaging

Coronal T1WIs post-gadolineum

Imaging

Sagital T1WI post-gadolineum

Imaging

Axial FLAIR

Discussion of Imaging Findings

CT with contrast shows a lobulated, peripherally enhancing mass in the left parietal-occipital lobe. Surrounding vasogenic edema extends to the splenium of the corpus callosum. There is mass effect on the trigone of the left lateral ventricle.

MR images show a 3.7 x 3.8 x 4.0cm lobulated mass with heterogenous peripheral enhancement and central low signal intensity in the left parietal-occipital lobe with extension to the cortex. Anteriorly there is vasogenic edema extending into the splenium of the corpus callosum. There is no morphologic evidence of tumor extension into the corpus callosum.

Differential Diagnosis based on imaging: Glioblastoma Multiforme vs. Metastasis

Operative procedure performed:Left parieto-occipital craniotomy and resection of mass

Pathology

Hematoxylin-Eosin, 4x: The tumor is comprised of sheets of uniform small blue cells with focal necrosis

Pathology

Hematoxylin-Eosin, 20x: The tumor cells are rounded with irregular hyperchromatic nuclei and small amounts of eosinophilic or clear cytoplasm

Pathology

MIB-1 Immunohistochemical Stain, 4x: Proliferation index is 20% to 50%

Pathology

CD99 Immunohistochemical Stain, 10x: Strong membranous staining of tumor cells

Pathology

Glial Fibrillary Acidic Protein (GFAP) Immunohistochemical Stain, 4x: Tumor component showing focal positivity

Pathology

CAM 5.2

Synaptophysin

AE1-3

CD45

Immunohistochemical Stains, 4x: No immunoreactivity

Diagnosis

Primitive Neuroectodermal Tumor, (PNET) WHO GRADE 4

Discussion

Supratentorial PNETs were once known as cerebral neuroblastomas. They are classified as a WHO grade IV, aggressive tumor. These tumors are typically solitary, well-circumscribed with irregular enhancement, and show cytic or necrotic areas. Calcifications and hemorrhagic components are not uncommon. PNETs are usually seen in children, and 80% occur in those less than 10 years of age. Only sporadic cases of PNETs in adults have been reported in the literature. Less than 1% of adult brain tumors are PNETs.