This tumor does not fit any classification from a preliminary look at the photos uploaded. There is a prominent rosette-like architectural pattern, and the nuclei of neoplastic cells appear very uniform and without anaplastic features. I call it rosette-like because these structures are not Homer-Wright rosettes, perivascular pseudorosettes, or Flexner-Wintersteiner rosettes. They are not those seen in rare papillary glioneuronal tumors, and are also slightly different from those encountered in rare rosetted glioneuronal tumors. I believe this is still a type of low grade (WHO grade II) fibrillary astrocytoma. I would do synaptophysin and NSE to rule out the unlikely possibility of a rosetted glioneuronal tumor. Without looking at more photos, these are my initial thoughts on this difficult case.

 Dear prof. mjma, thank you so much!

 We have done IHC of syn, and the result  of  which will be announced several days later.

 我倒是首先考虑rosetted glioneuronal tumor.

这种假乳头状结构不好用星胶来解释。我也不考虑乳头状脑膜瘤。

 This tumor does not fit any classification from a preliminary look at the photos uploaded. 从给我们的图像上看,该病例不适合任何一种肿瘤的分类,There is a prominent rosette-like architectural pattern, and the nuclei of neoplastic cells appear very uniform and without anaplastic features. 明显的菊形团样结构、非常一致性的胞核、没有异形性。I call it rosette-like because these structures are not Homer-Wright rosettes, perivascular pseudorosettes, or Flexner-Wintersteiner rosettes. 我说它是菊形团样结构，因其不是Homer-Wright 样菊形团或血管周的假菊形团，也不是Flexner-Wintersteiner 菊形团，They are not those seen in rare papillary glioneuronal tumors, and are also slightly different from those encountered in rare rosetted glioneuronal tumors.这种特点不见于罕见的乳头状胶质神经瘤，与罕见的菊形团性胶质神经瘤略有差别。 I believe this is still a type of low grade (WHO grade II) fibrillary astrocytoma. 我感觉仍然是低度纤维型星形细胞瘤(WHO grade II)。I would do synaptophysin and NSE to rule out the unlikely possibility of a rosetted glioneuronal tumor. 希望做synaptophysin 和 NSE，以排除菊形团性胶质神经瘤 Without looking at more photos, these are my initial thoughts on this difficult case. 本例为疑难病例，仅有的图像只能想到此处。

 最终诊断：乳头状胶质神经元肿瘤，WHO1～2级。WHO分类属于节细胞胶质肿瘤的亚型。

Syn散在细胞阳性和灶性片状阳性。

 至2006年，该肿瘤目前国外有33例报道，国内3例。