Samimi Kaveh, Gharib Mohammad Hadi, Rezaei-Kalantari Kiara, Jafari Maryam
Department of Radiology, Rasoul-e-Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Iran J Radiol. 2012 Nov;9(4):227-30. doi: 10.5812/iranjradiol.8766. Epub 2012 Nov 20.
Meningeal melanocytoma is a primary melanocytic neoplasm with certain MR and immunohistochemical characteristics worthy to note. In a 38-year-old man with a complaint of headache for a couple of years and recently added nausea, vomiting, diplopia, progressive visual blurring and hearing loss, magnetic resonance imaging (MRI) was remarkable for T1 shortening of leptomeninges and certain nodules in precontrast study. Subsequent contrast-enhanced MR imaging of the brain and spine revealed enhancement in the basal cisterns extending throughout the spinal canal. Contrast-enhanced MRI revealed diffuse enhancement in the basal cisterns extending throughout the spinal canal. Immunohistochemical analysis on one of the intraspinal nodules proposed leptomeningeal melanocytoma. The characteristic shortening of T1 and T2 relaxation times in MRI as a result of the paramagnetic stable free radicals that exist within melanin, often suggests a diagnosis of a melanocytic leptomeningeal process. Moreover, there are unique immunohistochemical characteristics for these varied lesions. In appropriate clinical settings, certain radiologic findings, especially both T1 and T2 shortening in nodular CNS lesions should propose meningeal melanocytoma.
脑膜黑素细胞瘤是一种具有某些值得注意的磁共振成像（MR）和免疫组化特征的原发性黑素细胞肿瘤。一名38岁男性，主诉头痛数年，近期出现恶心、呕吐、复视、进行性视力模糊和听力减退，磁共振成像（MRI）显示在平扫研究中软脑膜T1缩短并有某些结节。随后对脑和脊柱进行的增强MR成像显示脑基底池强化并延伸至整个椎管。增强MRI显示脑基底池弥漫性强化并延伸至整个椎管。对一个脊髓内结节进行的免疫组化分析提示为软脑膜黑素细胞瘤。由于黑色素中存在的顺磁性稳定自由基，MRI中T1和T2弛豫时间的特征性缩短常提示黑素细胞性软脑膜病变的诊断。此外，这些不同病变具有独特的免疫组化特征。在适当的临床情况下，某些影像学表现，尤其是中枢神经系统结节性病变中T1和T2均缩短，应考虑脑膜黑素细胞瘤。
