Luo Yuting, Wang Pingling, Zhan Qinru, Luo Jiao, Luo Baohong
Department of Pathology, The Seventh Affiliated Hospital of Sun Yat-Sen University, Shenzhen, China.
Department of Pathology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
Neuropathology. 2025 Feb;45(1):55-59. doi: 10.1111/neup.13002. Epub 2024 Sep 3.
ALK-positive histiocytosis is a rare histiocytic disease characterized by ALK positivity. It was first described in 2008 as a systemic disease in infants. The disease often shows positivity for CD68 and CD163 on immunohistochemistry, and genomic analysis frequently reveals KIF5B::ALK fusions. ALK-positive histiocytosis typically follows an indolent course and has a promising prognosis, with conventional treatments usually being effective. Here, we report a rare case of ALK-positive histiocytosis with exclusive involvement of the central nervous system in a 33-year-old Asian adult woman. Although cranial MRI suggested a meningioma, immunohistochemical workup showed that the ALK-positive tumor cells expressed macrophage/histiocyte markers such as CD163 and CD68. Additionally, second-generation sequencing revealed a KIF5B::ALK fusion. Our case highlights the importance of the differential diagnosis in adult central nervous system tumors, emphasizing the combination of morphology, immunophenotype, and molecular approach with ALK status evaluation to confirm a diagnosis of ALK-positive histiocytosis. This case also expands the clinicopathologic spectrum of ALK-positive histiocytosis.
ALK阳性组织细胞增多症是一种罕见的组织细胞疾病，其特征为ALK阳性。它于2008年首次被描述为一种婴儿系统性疾病。该疾病在免疫组织化学上常显示CD68和CD163阳性，基因组分析经常揭示KIF5B::ALK融合。ALK阳性组织细胞增多症通常病程进展缓慢，预后良好，常规治疗通常有效。在此，我们报告一例罕见的ALK阳性组织细胞增多症，仅累及一名33岁亚洲成年女性的中枢神经系统。尽管头颅MRI提示为脑膜瘤，但免疫组织化学检查显示ALK阳性肿瘤细胞表达巨噬细胞/组织细胞标志物如CD163和CD68。此外，二代测序揭示了KIF5B::ALK融合。我们的病例强调了成人中枢神经系统肿瘤鉴别诊断的重要性，强调形态学、免疫表型和分子方法与ALK状态评估相结合以确诊ALK阳性组织细胞增多症。该病例还扩展了ALK阳性组织细胞增多症的临床病理谱。
