Department of Pathology, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
Suzhou Municipal Hospital, Suzhou Hospital Affiliated to Nanjing Medical University, Suzhou, Jiangsu, China.
Histol Histopathol. 2022 Dec;37(12):1253-1259. doi: 10.14670/HH-18-550. Epub 2022 Nov 11.
To investigate the histological and immunohistochemical features of primary ectopic meningiomas (PEMs), especially those of primary ectopic atypical meningiomas (PEAMs).
We examined 6 cases of PEM, including 2 PEAM cases, which occurred separately in left nasal cavity, left lower lung, right neck, left orbit, right upper lung, and left upper lung by histological and immunohistochemical analysis. In general, of the 6 PEM cases analyzed, 4 cases exhibited morphology of Grade Ⅰ, including 1 fibrous, 1 meningothelial, and 2 transitional variant. The remaining 2 cases shared similar atypical morphology of Grade Ⅱ. The tumors were distributed in sheet-like patterns with loss of architecture of classic meningiomas. Significant hypercellularity, multi-focal necrosis, and thin-walled blood vessels were identified. The mitotic figures were estimated at 6 per 10 high-power fields in one case, and 8 mitotic figures in another. Immunohistochemically, the 6 PEM cases were all positive for Vimentin and EMA, while none showed immunostaining for CKpan, S-100, CD34, STAT6, SMA, Syn or Bcl-2. 4 PEM cases of Grade Ⅰ were immunoreactive for PR but negative for P53, while the 2 PEAM cases displayed negative staining for PR but positivity for P53. As for Ki-67, the positive staining of 4 Grade Ⅰ cases was no greater than 2%, while the positive rates of the 2 PEAM cases were 10% and 20%.
Our study has expanded cases of PEMs, especially the 2 PEAM cases in rare sites. Our study has also further summarized the pathological features of PEMs, focusing on the histological features of PEAMs, and the immunohistochemical features worthy of further investigations.
研究原发性异位脑膜瘤（PEM），尤其是原发性异位非典型脑膜瘤（PEAM）的组织学和免疫组织化学特征。
我们通过组织学和免疫组织化学分析，检查了 6 例 PEM，包括 2 例 PEAM，分别发生在左鼻腔、左下肺、右颈部、左眼眶、右上肺和左上肺。总的来说，在分析的 6 例 PEM 中，有 4 例表现为Ⅰ级形态，包括 1 例纤维型、1 例脑膜上皮型和 2 例过渡变异型。其余 2 例具有类似的Ⅱ级非典型形态。肿瘤呈片状分布，失去了经典脑膜瘤的结构。明显的细胞增多、多灶性坏死和薄壁血管。一个病例的有丝分裂数为每 10 个高倍视野 6 个，另一个病例为 8 个有丝分裂数。免疫组化染色显示，6 例 PEM 均为波形蛋白和 EMA 阳性，而 CKpan、S-100、CD34、STAT6、SMA、Syn 或 Bcl-2 均为阴性。4 例Ⅰ级 PEM 对 PR 呈免疫反应性，但对 P53 呈阴性，而 2 例 PEAM 则对 PR 呈阴性，对 P53 呈阳性。Ki-67 阳性染色在 4 例Ⅰ级病例中不超过 2%，而在 2 例 PEAM 病例中为 10%和 20%。
我们的研究扩大了 PEM 的病例，特别是罕见部位的 2 例 PEAM。我们的研究还进一步总结了 PEM 的病理特征，重点是 PEAM 的组织学特征和值得进一步研究的免疫组织化学特征。
