Contributed by Fabrice Chrétien MD1,2, Michel Djindjian MD, PhD3, Philippe Caramelle1, Frederic Ricolfi MD, PhD4, Christo Christov MD, PhD2,5
1INSERM EMI 0011, Université Paris XII, Créteil, France. 2Service d'Histologie 3Service de Neurochirurgie, 4Service de Neuroradiologie, 5INSERM U421, Université Paris XII, Créteil, France Hôpital Henri Mondor AP-HP, 94010 Créteil cedex, France,
A 42-year-old man was admitted to the neurosurgery department because of paraparesis and sensory deficits of both feet. The CT scan and MRI examination revealed a solitary intramedullary lesion bulging dorsally from the thoracic spine (T4 level) (Figure 1). Spinal angiography revealed the dense vascularity of the lesion, the presence of feeding and draining vessels, as well as intra-lesional shunting. A gross total resection was performed.
Examined at low power, the lesion was a densely cellular, highly vascularized tumor (Figure 2). Malformative vessels of different calibers were conspicuous, some were dilated with thickened sclerotic walls (Figure 3). In addition, vessel walls were encrusted with more or less abundant deep-blue dot-like or laminated material (Figure 4); some larger accumulations of it were easily recognizable as "tombstones" of obliterated vessels (Figure 5). Areas separating these vascular channels were dominated by sheets of immature looking mostly round or vaguely spindled cells with indistinct cell borders (Figures 6, 7). Larger ones with irregular nuclei, course chromatin, and more abundant eosinophilic cytoplasm were easily found (Figure 6). So were mitoses (Figure 6) and foci of necrosis (Figure 7, 8). At closer look, a second minor population was identified consisting of large, oval cells with central nuclei, large nucleoli, and cytoplasm in which fine pale granulations were present (Figures 9, 10); few of these cells were bi-nucleated (Figure 11). Focally, these large cells were embedded in a more prominent fiber background created by spindle cells with coarse eosinophilic processes (Figure 10).
By immunohistochemical examination, most cells were immunopositive for GFAP (Figure 12). Cells of the second type, as well as some of the smaller non-descript cells, showed in their majority a granular perimembranous synaptophysin staining (Figure 13). Rare cell were unequivocally immunopositive for CD34 (Figures 14, 15), chromogranin A (Figure 16), and neurofilament (Figures 17, 18). Most of these labelings highlighted the tendency of these cells to cluster in a perivascular position. The highest MIB1 proliferation index was 25% (Figure 19).