原发性黑素细胞病变是一组起源于软脑膜黑素细胞的、呈弥漫性或局限性生长的良、恶性肿瘤 ,包括 :①弥漫性黑素细胞增生症 ;②黑素细胞瘤 ;③恶性黑素瘤 ;④脑膜黑素瘤病。可出现交界性或混合性肿瘤。弥漫性黑素细胞增生症的CT和MRI表现为软脑膜的弥漫性增厚、强化。黑素细胞瘤内如含有较多的黑素 ,则表现为T1WI高信号、T2WI低信号 ,增强时肿瘤通常出现均匀强化表现。恶性黑素瘤也可表现为T1WI高信号、T2WI低信号 ,主要取决瘤体内黑素含量和是否伴有出血 ,增强时肿瘤通常也出现均匀强化表现。脑膜黑素瘤病可以表现为脑内外多发的T1WI高信号、T2WI低信号结节影 ,增强后可出现脑膜的弥漫性强化和(或)脑内的结节状强化。原发性黑素细胞病变的上述这些影像学表现都是非特异性的 Primary melanocytic lesions are a group of benign and malignant tumors of diffuse or localized growth originating from leptomeningeal melanocytes including: diffuse melanocytosis; melanocytoma; Malignant melanoma; ④ meningioma disease. There may be borderline or mixed tumors. Diffuse melanocytic hyperplasia of the CT and MRI showed diffuse thickening of the pia mater, enhanced. If there are more melanocytomas melanoma, the performance of T1WI high signal, T2WI low signal, enhance the tumor usually appear even enhanced performance. Malignant melanoma can also be manifested as T1WI high signal, T2WI low signal, mainly depending on tumor melanin content and whether accompanied by bleeding, enhanced tumor usually appear uniform enhancement. Meningeal melanoma can be manifested as multiple high-signal T1WI brain, T2WI low signal nodules, enhancement of diffuse meninges and / or nodular enhancement of the brain. These imaging findings of primary melanocytic lesions are nonspecific