Teaching NeuroImage: Intradural ALK-Positive Histiocytosis With Involvement of Nerve Roots and Spinal Dura

作者：Huanyu Luo, Yun Peng · 发表于：Neurology · 年份：2022 · DOI：10.1212/wnl.0000000000200550 · 被引用次数：7 · 研究领域：Histiocytic Disorders and Treatments、Tuberous Sclerosis Complex Research、Eosinophilic Disorders and Syndromes

A 3-year-old boy presented with progressive lower extremity weakness and difficulty walking for 2 months. Neurologic examination found the muscle strength of his left lower limb was grade 3 and tendon reflex was weakened. MRI demonstrated an intradural extramedullary mass between T10-11 with multiple and diffuse enhancement of thickened nerve roots and spinal dura (Figure). Juvenile xanthogranuloma was suspected as positive staining for CD68 and negative for S100 and CD1a, while immunoreactivity for ALK did not support it. The genetic test confirmed the diagnosis of ALK-positive histiocytosis with KIF5B-ALK fusion, which is a relatively new subtype of histiocytic disease.1,2