Department of Neurosurgery and Oncology of the Central Nervous System, Medical University of Lodz, Poland.
Folia Neuropathol. 2012;50(2):187-93.
We report here common ultrastructural findings in a short list of meningiomas. At the lower power magnification, a tumour consisted of elongated or round cells and innumerable cellular processes connected with diverse intercellular junctions. Nuclei presented no specific features, nucleoli were infrequently seen and heterochromatin was clumped beneath the nuclear membranes. In a case of clear cell meningioma, cells were of watery cytoplasm. Occasionally, immobile cilia, completely ensheathed by the cytoplasm and anchored by blepharoplasts were seen; as we did not encounter those rare cilia in cross-sections, no further insight into their inner microtubular-doublet structure was possible. The cytoplasm of the cells and the processes were filled with the intermediate filaments. In the intercellular space, collagen fibrils and electron-dense material was occasionally observed. The majority of the tumour samples were filled with processes. Several types of junctional complexes were observed. The most frequent were desmosomes and in the proper plane of section their whole pentalaminar structure was readily discernible. However, robust tonofilaments, as seen in epithelial neoplasms, were not observed. Those desmosomal junctions were either completely symmetric or asymmetric, but the exact symmetry could not be judged without the assistance of a goniometer. Some junctional complexes were more elaborate, with desmosomal junctions separated by a tight apposition of membranes, which suggests tight junctions. "Intranuclear vacuoles" well-visible even at low power were defined as indentation of the cytoplasm into the nucleus. Within these vacuoles, autophagic vacuoles and lysosomal bodies were seen, suggesting an active macroautophagy process. In 2 cases, severe lipidization of meningioma cell cytoplasm was observed. In a case of anaplastic meningioma, a mitotic figure was found. In another case, empty rectangular spaces in the cytoplasm, suggestive of pre-existing crystalloid structures, were seen.
我们在此报告一系列脑膜瘤的常见超微结构发现。在低倍放大下，肿瘤由拉长或圆形细胞以及无数与各种细胞间连接的细胞突起组成。细胞核无特殊特征，核仁罕见，异染色质聚集在核膜下。在透明细胞脑膜瘤的病例中，细胞呈水样细胞质。偶尔可以看到不动的纤毛，完全被细胞质包裹并被眼点锚定；由于我们在横截面上没有遇到那些罕见的纤毛，因此无法进一步了解其内部微管双联体结构。细胞和突起的细胞质充满了中间丝。在细胞间隙中，偶尔可以观察到胶原纤维和电子致密物质。肿瘤样本的大部分充满了突起。观察到几种类型的连接复合体。最常见的是桥粒，在适当的切片平面上，其完整的五夹板结构很容易识别。然而，没有观察到上皮性肿瘤中所见的粗壮张力丝。这些桥粒连接要么是完全对称的，要么是不对称的，但如果没有量角器的帮助，就无法判断其确切的对称性。一些连接复合体更加复杂，桥粒连接被紧密贴合的膜隔开，提示紧密连接。甚至在低倍放大下也能清晰可见的“核内空泡”被定义为细胞质向细胞核的凹陷。在这些空泡中，可以看到自噬空泡和溶酶体，表明存在活跃的巨自噬过程。在 2 例脑膜瘤中观察到严重的细胞质脂质化。在间变性脑膜瘤的病例中发现有有丝分裂象。在另一个病例中，细胞质中出现了空的矩形空间，提示存在预先存在的结晶结构。
