Contributed by Akosua B. Domfeh, MBchB and Geoffrey Murdoch, MD
Published on line in October 2005
A 60-year-old man presented with a history of headaches. An MRI revealed a calcified enhancing partially cystic, partially solid right parieto-occipital mass (Figure 1). A craniotomy was performed and intra-operative consultation was requested.
INTRA-OPERTIVE CONSULTATION and GROSS EXAMINATION:
Received multiple fragments of irregular gritty to almost calcified tissue, 2.5 X 1.0 X 0.5cm in aggregate of which part was used for touch preparations. Touch preparations showed basophilic clumps of calcified material (Figure 2). Also received was a yellow, soft tissue fragment 1.0cm used for the smear preparations. Intraoperative smear preparations revealed a relatively hypocellular smear with a fibrillary background, reactive astrocytes and entrapped large neurons some of which were binucleate (Figures 3 and 4).
An intra-operative diagnosis was rendered and the surgeon completed the excision of the mass.
Hematoxylin and Eosin (H & E) permanent sections of the material used for the smear revealed a haphazard arrangement of large atypical neurons (Figure 5). On a higher magnification, some of these neurons showed binucleation (Figure 6). There were also scattered foci of perivascular lymphocytes present in these sections (Figure 7). H & E sections of the calcified and gritty material used for touch preparations revealed a lesion composed of focal nodular - lobular faintly eosinophilic to basophilic amorphous chondromyxoid hypocellular to acellular material in association with bone and fibrous tissue (Figures 8 and 9). There was also an associated peripheral palisading of spindle cells around these nodular matrixes (Figure 10). The bone consisted of both woven and cancellous bone and seems to be arising from the fibrous tissue (Figure 11). In some areas this lesion was seen in between and around neuropil with reactive astrocytes (Figure 12). There was no mitoses or necrosis in association with this lesion.
SPECIAL AND IMMUNOHISTOCHEMICAL STAINS:
Immunohistochemical stains were performed on sections from the soft tissue component. Neu N and synaptophysin highlighted the abnormal neurons (Figures 13 and 14) Cresyl violet stain highlighted the ganglion cells (Figure 15) with GFAP highlighting the reactive astrocytes (Figure 16). Ki67 revealed no cells in the proliferative phase (Figure 17).