Department of Pathology, University of Oklahoma Health Sciences Center

NeuroTest Sample Question #46 Next question Previous question

Answer: E (High grade astrocytoma) Level of difficulty: 2 NeuroTest NeuroLearn NeuroHelp

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Discussion: 

• Pathology of the case: The background is dirty looking and indicates necrosis (Panel A). There are quite some bluish mucoid material (Þ) which is not uncommon for glial neoplasm with mucoid changes. There are many large, eosinophilic cells with eccentrically located, large, and pleomorphic nuclei (Þ). There are also elongated cytoplasmic processes (Þ) that are typically seen in glial neoplasms. Putting these features altogether, these cells are neoplastic gemistocytic astrocytes. The gemistocytic cells are also well appreciated in the frozen section (Panel B). Some neoplastic cells without gemistocystic changes can also be appreciated in both the cytologic and frozen section preparations. [Click here to see the cytologic preparation of a pilocytic astrocytoma to comparison the differnce in nuclear morphology]

• Langerhans' histiocytosis: The frontal lobe is an extremely rare location for primary or secondary Langerhans's histiocytosis. The neoplastic Langerhan's cell has characteristic nuclear groove and do not usually exhibit the degree of pleomorphism being illustrated here. [Click here to see Langerhans's histiocytosis]

• Primitive neuroectodermal tumor (PNET): PNET can occur in this location and in this age group. The morphologic features of PNET is very similar if not identical to medulloblastomas. In essense, PNET and medulloblastoma are small blue cell with a minimal rim of cytoplasm. Many of the nuclei are naked. In general the nuclei are relatively monotonous but a higher degree of variation in nucelar size can be appreciated in the cytologic preparations than frozen sections or paraffin sections. Typically, the nuclei have a dirty "salt and pepper" suggestive of neuroendocrine differentiation. Nuclear groove can be seen in some nuclei. Medulloblastoma do not arrange in papillary structures as in this case. The tumor cells in this case has too much cytoplasm and the nuclei lacks the characteristic "salt and pepper" neuroendocrine appearance. [Click here to see comparison of cytologic features] The cells under discussion have a substantial amount of cytoplasm and the characteristic elongated cytoplasmic process that are seen in glial neoplasm. These features put PNET out of consideration.
• Eosinophils: The cells look eosinoiphic but the nuclei are large, hyperchromatic and pleomorphic. If you have been seriously entertaining this diagnosis, you have very good imagination.
• Germinoma: They  typically have large eosinophilic nucleli and large nucleoli. In most cases, they are admixed with lymphocytes and some lymphocytes could be identified in the cytologic preparations. In contrast, promininet nucleoli is very uncommon in glial neoplasm. [Click here to see the two cell population on histologic section of a germinoma]

Comment: KarMing-Fung@ouhsc.edu