Calcifying pseudoneoplasm of neuroaxis (CAPNON) is a rare lesion of the central nervous system with uncertain histogenesis. We further explored phenotypic spectrum of the entity with respect to possible histogenesis. We collected 5 cases of CAPNONs, performed a detailed morphological assessment, and performed an extensive immunohistochemical analysis (EMA, progesterone receptors, MUC4, SSTR2A, cytokeratin AE1/3, cytokeratin 18, GFAP, neurofilaments, desmin, nestin, synaptophysin, S100 protein, SOX10, CD56, Podoplanin, SATB2, ERG, CD45, and CD163) to elucidate the histogenesis. Furthermore, we performed NGS analysis of one case. The clinical course was benign in all cases. All lesions showed extensively calcified matrix in multilobular arrangement, with a palisade of osteoblast-like cells. Characteristic fibrohyaline matrix was notable in 4/5 cases, while one case was myxoid with rod-like calcifications. Metaplastic lamellar bone was present in 4/5 cases and psammoma bodies were present in 2/5 cases. In 4/5 cases, areas of entrapped glial tissue were present. Expression of EMA was focally present in 3/5 cases, SSTR2A and nestin in 2/5 cases, and progesterone receptor in 2/5 cases in rare cells. We did not observe concomitant expression of EMA, SSTR2A, and progesterone receptor in the same cellular subsets. In one case, NGS showed multiple chromosomal alterations and missense mutation in PIK3CA, attributable to the admixed meningothelial population compatible with meningioma. In another case, biphasic proliferation with myoepithelial phenotype was present. The lesions showed no lineage-specific immunoprofile. Additional pathology was identified in two cases, furthermore suggestive of a possible reactive origin of the lesion.

神经轴钙化性假瘤（CAPNON）是一种罕见的中枢神经系统病变，组织发生不确定。我们进一步探索了实体在可能的组织发生方面的表型谱。我们收集了 5 例 CAPNON，进行了详细的形态学评估，并进行了广泛的免疫组织化学分析（EMA、孕酮受体、MUC4、SSTR2A、细胞角蛋白 AE1/3、细胞角蛋白 18、GFAP、神经丝、结蛋白、巢蛋白、突触素、S100 蛋白、 SOX10、CD56、Podoplanin、SATB2、ERG、CD45 和 CD163）以阐明组织发生。此外，我们对一个病例进行了 NGS 分析。所有病例的临床过程都是良性的。所有病灶均呈多叶排列的广泛钙化基质，有成骨细胞样细胞栅栏。4/5 病例有明显的特征性纤维透明质基质，1例为粘液样伴有棒状钙化。4/5 例存在化生板层骨，2/5 例存在砂粒体。在 4/5 的病例中，存在被包裹的神经胶质组织区域。在稀有细胞中，EMA 的表达在 3/5 例中，SSTR2A 和巢蛋白在 2/5 例中，黄体酮受体在 2/5 例中。我们没有观察到 EMA、SSTR2A 和孕酮受体在相同细胞亚群中的伴随表达。在一个案例中，NGS 显示出多处染色体改变和错义突变 和黄体酮受体在稀有细胞中的 2/5 例。我们没有观察到 EMA、SSTR2A 和孕酮受体在相同细胞亚群中的伴随表达。在一个案例中，NGS 显示出多处染色体改变和错义突变 和黄体酮受体在稀有细胞中的 2/5 例。我们没有观察到 EMA、SSTR2A 和孕酮受体在相同细胞亚群中的伴随表达。在一个案例中，NGS 显示出多处染色体改变和错义突变PIK3CA，归因于与脑膜瘤相容的混合脑膜上皮群体。在另一种情况下，存在具有肌上皮表型的双相增殖。病变显示没有谱系特异性免疫谱。在两个病例中发现了额外的病理学，进一步提示病变可能是反应性起源。