Brain Pathology Case of the Month - October 2018

Contributed by Eun Jung Koh, MD1; Seung-Ki Kim, MD, PhD2; Sung-Hye Park, MD, PhD3; Ji Yeoun Lee, MD, PhD2; Kyu-Chang Wang, MD, PhD2; Ji Hoon Phi, MD, PhD2
1Department of Neurosurgery, Dongguk University Ilsan Hospital, Goyang, Korea
     2Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul, Korea
     3Department of Pathology, Seoul National University Hospital, Seoul, Korea


We present 2 cases of cerebellar mass of male infants. Case 1 is a 15-month-old male infant presented with irritability, poor oral intake and vomiting. Brain magnetic resonance (MR) imaging revealed a 5.24.4 cm-sized mass in the left cerebellar hemisphere. The tumor showed robust gadolinium-enhancement and a mixed solid and cystic architecture without intratumoral hemorrhage (Fig 1A). The elective tumor resection was performed through paramedian suboccipital approach. The tumor was huge and hypervascular but friable. The tumor was well-demarcated and removed totally. The patient had no additional neurological deficit postoperatively. The baby received adjuvant chemotherapy. He has lived without neurological deficit or tumor recurrence for 17 months of follow-up.

Case 2 is a 16-month-old male infant who presented to emergency room for recurrent vomiting and lethargy. Brain MR imaging showed 4.94.8 cm-sized enhancing mass with internal hemorrhage in the left cerebellar hemisphere and obstructive hydrocephalus (Fig 2A). The tumor resection was performed through paramedian suboccipital approach. The tumor was whitish and soft but hypervascular. Postoperative brain MR showed 1.11.2 cm-sized residual tumor abutting tentorium cerebelli and transverse sinus. The patient underwent re-operation for the removal of the residual lesion after 5 days. Finally, the tumor was removed totally. The patient received adjuvant chemotherapy. He has presented regular outpatient clinic without tumor recurrence until 25 months of follow-up.


In case 1, hematoxylin and eosin stained section showed loosely arranged polygonal shaped tumor cells with hyperchromatic nuclei. There was a structure consisted of a central vessel surrounded by cuboidal tumor cells in a cystic space (Fig 1B). The tumor cells were positive for CD117 (c-kit) (Fig 1C), and alpha-fetoprotein (AFP) (Fig 1D). No reactivity for CD30 and -human chorionic gonadotropin (β-HCG) and placental alkaline phosphatase (PLAP) was observed.

In case 2, hematoxylin and eosin stained section revealed central blood vessels with surrounding rosette-like arrangement of tumor cells (Fig 2B). Immunohistochemically, the Ki-67 proliferation index was 71.15%. CD117 (Fig 2C), pan-cytokeratins, and AFP (Fig 2D) were positive in this tumor cells. The tumor cells were negative for CD30, β-HCG, PLAP, programmed death 1 (PD-1), and programmed death-ligand 1 (PD-L1). What are the diagnoses?


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