Brain Pathology Case of the Month - November 2015

Contributed by Kyung Jin Seo, MD, PhD1, Tae-Gyu Lee, MD, PhD2, Young Joo Kim, MD, PhD3, Hyunjong Kim, MD, PhD4, Hye Sung Won, MD5, Ok Ran Shin, MD. PhD1
Departments of 1Hospital Pathology, 2Neurosurgery, 3Radiology, 4Laboratory Medicine, and 5Internal Medicine
    College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea


A 30 year-old man presented with progressive visual field defect, headache and nausea. He had a history of occipital area blunt head injury (hit by an iron pipe at work) three months before referral to our clinic. The initial diagnosis at the local clinic was brain contusion and concussion. On the initial X ray no skull fracture was detected. However, owing to a progressive visual field defect and dizziness, epidural hemorrhage was suspected. A burr-hole trephination for drainage was subsequently performed. Unexpectedly, the operating neurosurgeon found a tumor mass instead of hematoma. Although the biopsy sample was obtained, only H&E slides were made without ancillary immunohistochemical stains (IHC). He was then transferred to our hospital for further evaluation and more tissue was obtained. The patient had no history of malignancy. All laboratory findings were within normal ranges, except AST 67 U/L (Normal range: 14-40), ALT 164 U/L (Normal range: 8-46) and serum lactated dehydrogenase (LDH) 532 U/L (Normal range: 218-472). Serologic tests for hepatitis, syphilis, and HIV infection were negative. Magnetic resonance imaging (MRI) revealed an epidural mass, approximately 7.0x6.8x4.1 cm, with extracranial extension forming a coffee bean shaped mass crossing the parieto-occipital lobe dura (Figs. 1, 2 and 3). The epidural mass was hyperintense to isointense to gray matter on T2 weighted images (WI) (Fig. 1), isointense on T1WI (Fig. 2). Following contrast infusion, the epidural mass showed marked heterogeneous enhancement but the extracranial mass did not (Fig. 3). In view of the radiologic findings, a clinical diagnosis of meningioma was considered and the patient underwent a brain biopsy to confirm the nature of the brain lesion.


On microscopic examination, both masses showed highly cellular tumors with the same morphologic features and focal necrosis (Fig. 4). At high power, the tumor cells were monotonous with large oval or pleomorphic nuclei, minute but distinct nucleoli and scant eosinophilic cytoplasm (Fig. 5). The calvarium was diffusely infiltrated by tumor cells (Fig. 6). IHC revealed the majority of tumor cells were strong positive for CD117 (Fig. 7), lysozyme (Lys) (Fig. 8), CD99 (Fig. 9) and were negative for LCA, CD20, CD3, CD34, CD56, and myeloperoxidase (MPO). A few tumor cells were positive for CD68/KP1 (Fig. 10). Bone marrow biopsy revealed no abnormalities. Abdominal computed tomography (CT) and torso positron emission tomography (PET) showed no tumor involvement in other organs. What is your diagnosis? What is your diagnosis?


International Society of Neuropathology