Kapur Payal, Selim M Angelica, Roy Lonnie C, Yegappan Mani, Weinberg Arthur G, Hoang Mai P
Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9073, USA.
Mod Pathol. 2005 Feb;18(2):197-204. doi: 10.1038/modpathol.3800281.
A subset of Spitz nevi poses substantial diagnostic difficulty, even among experts, due to its resemblance to malignant melanoma. These lesions are termed atypical Spitz nevi/tumors and there is currently a lack of objective criteria for predicting their biologic behavior. We compared the expression of Ki-67, p21, and fatty acid synthase by immunohistochemistry in 10 atypical Spitz nevi, 28 typical Spitz nevi, 19 compound melanocytic nevi and 18 invasive malignant melanomas. There was a progressive increase in fatty acid synthase cytoplasmic expression with statistically significant differences observed between Spitz nevi and atypical Spitz nevi (P=0.003) and between atypical Spitz nevi and malignant melanoma (P<0.050). Ki-67 nuclear staining was lower in both typical and atypical forms of Spitz lesions than in malignant melanoma (P<0.001). The degree of P21 nuclear expression in atypical Spitz nevi was not significantly different than in Spitz nevi, but was significantly greater than expression in conventional nevi and approached significance after multiple comparisons corrections for malignant melanoma. Thus, a high level of P21 expression makes a tumor more likely to be a typical or atypical Spitz nevus than a malignant melanoma, especially when coupled with a low Ki-67 index and weak expression of fatty acid synthase. These immunohistochemical observations support the concept that atypical Spitz nevi are distinct lesions of borderline biologic behavior residing between Spitz nevi and malignant melanoma. The study also compared a large array of histologic features of 16 cases of typical Spitz nevi in children with 12 typical Spitz nevi in adults. The adult lesions were significantly more likely to be intradermal and to display dermal fibroplasia, but were histologically similar to their pediatric counterparts in all other respects.
一部分Spitz痣即使在专家中也会造成很大的诊断困难，因为它与恶性黑色素瘤相似。这些病变被称为非典型Spitz痣/肿瘤，目前缺乏预测其生物学行为的客观标准。我们通过免疫组织化学比较了10例非典型Spitz痣、28例典型Spitz痣、19例复合性黑素细胞痣和18例浸润性恶性黑色素瘤中Ki-67、p21和脂肪酸合酶的表达。脂肪酸合酶的细胞质表达呈逐渐增加趋势，在Spitz痣与非典型Spitz痣之间（P=0.003）以及非典型Spitz痣与恶性黑色素瘤之间（P<0.050）观察到统计学上的显著差异。Ki-67核染色在典型和非典型形式的Spitz病变中均低于恶性黑色素瘤（P<0.001）。非典型Spitz痣中P21核表达程度与Spitz痣无显著差异，但显著高于传统痣，在对恶性黑色素瘤进行多次比较校正后接近显著水平。因此，高水平的P21表达使肿瘤更有可能是典型或非典型Spitz痣而非恶性黑色素瘤，特别是当与低Ki-67指数和脂肪酸合酶弱表达相结合时。这些免疫组织化学观察结果支持了这样的概念，即非典型Spitz痣是介于Spitz痣和恶性黑色素瘤之间具有边缘生物学行为的独特病变。该研究还比较了16例儿童典型Spitz痣与12例成人典型Spitz痣的大量组织学特征。成人病变更有可能位于真皮内并显示真皮纤维增生，但在所有其他方面组织学上与其儿童对应物相似。
