Contributed by Namita Sinha1 MD, Jill Wooff2, Jai J S Shankar3, Peter Gorman4, Robert J Macaulay5
Departments of 1Pathology and 3Radiology-Neuroradiology, Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia; 2Pathology, Regina General Hospital, University of Saskatchewan College of Medicine, Regina, Saskatchewan; 4The Moncton Hospital, Moncton, New Brunswick, Canada; and 5Department of Pathology, H. Lee Moffitt Cancer Center, Tampa, FL, USA.
CLINICAL HISTORY AND IMAGING
A 48-year-old right handed female presented with a 6 month history of progressive decrease of sensation in right upper and lower extremities following a fall after returning from a golf course. She attributed that fall to the loss of sensation, which improved spontaneously over 10 minutes with some residual numbness in the right leg. Her symptoms progressed and she developed difficulty in walking and lifting her right leg. She also complained of neck discomfort and chronic headaches. Neurological examination revealed mild patchy loss of pinprick and light touch sensation in the right upper and lower extremity and trunk with no consistent dermatomal distribution. There was diminished vibration sensation in the right knee. Deep tendon reflex was absent in the right ankle. Plantar reflexes were downgoing. Her gait was stiff with mild circumduction of the right leg. Rest of the motor and cranial nerve examinations were grossly normal.
Magnetic Resonance Imaging (MRI) of brain and cervical spine showed a heterogeneous T2 hyper-intense (Figure 1) and T1 hypointense (Figure 2) intramedullary lesion at the C1-C2 levels. Post contrast T1 images showed heterogeneous enhancement of the mass with areas of non-enhancement suggestive of cystic change or necrosis (Figure 3). The T2 hyperintensity extended beyond the enhancing areas suggestive of edema (Figure 1). There was no other enhancing lesion. Imaging features suggested ependymoma; other possibilities were astrocytoma or less likely hemangioblastoma.
A C1-3 laminectomy and midline myelotomy was performed with gross total resection of the tumor. Intraoperative diagnosis was ependymoma,; although this was thought to be supported on permanent sections, the case was referred in consultation to our institution before final sign-out.
GROSS AND MICROSCOPIC PATHOLOGY
The specimen was received piecemeal from the operating room. Histopathological examination revealed a moderately to markedly hypercellular neoplasm, surrounded by compressed CNS tissue (Figure 4). There were numerous conspicuous perivascular rosettes (Figure 5) but no ependymal rosette or canal. The tumor was composed of small cells with scant finely granular eosinophilic cytoplasm and round, monomorphic nuclei with dispersed chromatin (Figure 6). Rare mitotic figures were present. Focal areas of the neoplasm were less cellular and composed of disorganized atypical moderate to large cells with abundant basophilic cytoplasm and large nuclei with prominent nucleoli (Figure 7); scattered cells were multinucleated.
The neoplastic cells were diffusely synaptophysin positive (Figure 8). In the areas containing larger cells, neurofilament was also positive (Figure 9). The tumor cells were negative for chromogranin, EMA, and CD99. Scattered cells were positive for GFAP, which showed a network of fine processes between many tumor cells (Figure 10). Ki-67 labeling was scant, <1%. No anaplastic features were identified. What is your diagnosis?