Contributed by Marco Gessi1, Gerrit H. Gielen1, Raoul Hinze2, Hans-Peter Vinz3, Christian GŁttel4 and Torsten Pietsch1
1Inst of Neuropathology, University of Bonn medical Center, Bonn, Germany; Inst. of 2Pathology
3Radiology and 4 Paediatrics, Helios Klinikum, Schwerin, Germany
An 11 years old male patient suffered from a blunt head injury after tumbling in consequence of a short episode of vertigo and visual disturbances. Thereafter, the patient was not responsive to verbal stimuli for approximately 10 minutes and presented a retrograde amnesia. No aconuresis was observed. In the first clinical examination, the patient showed an anisocoria with a smaller pupil on the left side and only a partial light reaction. A prominent dysdiadochokinesia could be observed. EEG did not detect any epileptogenic foci but a focal wave slowing compatible with a right parieto-occipital tumor or with an intracerebral bleeding. The consecutive MRI of the neuroaxis showed an intra-axial lesion with solid parts and contrast enhancing, cystic areas (Figs. 1A-B), located in the right occipital lobe. Notably, the skull bone in the proximity of the lesion appeared thinned (Fig. 1B, arrow) but without any signs of infiltration. MRI imaging of the spine was without pathological findings. The family history was not suspicious for cancer predisposition syndromes. The lesion was surgically completely resected (Fig. 1C) and submitted to neuropathological examination (Fig. 2). The postoperative course was uneventful.
The histopathological examination revealed a highly cellular, glial tumor (Fig. 3). The tumor presented perivascular architecture with evidence of perivascular pseudorosettes (Fig. 3). The tumor cells mostly showed hyperchromic nuclei with rounded shaped contour and scant cytoplasm (Fig. 3). Mitoses were evident. No areas of necrosis were observed. Focally, the tumor showed an area composed by cells with large, eosinophilic, granular, PAS positive cytoplasms (Figs. 4 and 5). This area, which appeared well demarcated from the surrounding tumor tissue (Fig. 6), presented a moderate cellularity and no marked nuclear polymorphism (Fig. 4). No mitoses were present herein.
Both tumor components were GFAP positive (Fig. 7) and showed a variable staining intensity with MAP2C. A dot-like and ring-like immunohistochemical staining pattern of EMA was focally present (Fig. 8). Moreover, the tumor cells were negative for Olig-2. Immunostainings with antibodies against p53, synaptophysin, CD34 and neurofilament protein resulted negative. The proliferation activity evaluated with Ki-67 (MIB-1) antibody was comprised between 20-25% in the highly cellular areas (Fig. 9), but only 2-3% in granular cell areas (Fig. 10). What is your diagnosis?