Hillesheim Paul B, Slone Steve, Kelley Denise, Malone Janine, Bahrami Soon
Department of Pathology and Laboratory Medicine, University of Louisville, Louisville, KY 40202, USA.
J Cutan Pathol. 2011 Jul;38(7):565-9. doi: 10.1111/j.1600-0560.2011.01688.x. Epub 2011 Mar 1.
Evaluation of cutaneous pigmented lesions can be diagnostically challenging and represents an activity often supplemented by immunohistochemistry. Immunohistochemical studies typically employ 3,3'-diaminobenzidine (DAB) resulting in brown staining of both melanocytes and melanin. Difficulty may thus arise in distinguishing different cell types in heavily melanized lesions. Azure blue counterstaining has been used in conjunction with melanoma antigen recognized by T-cells (MART-1) to differentiate melanocytes from melanin by highlighting the latter blue-green. Microphthalmia transcription factor (MiTF) represents an alternative immunomarker that shows nuclear reactivity, which facilitates ease of interpretation.
Twenty examples of solar lentigo and melanoma in situ (MIS) were independently evaluated utilizing MiTF and MART-1/Azure blue for melanocyte quantification. Melanocyte counts were averaged over five high-power fields (×400) to obtain a mean melanocytic count.
There was no significant difference in the mean melanocytic count between MART-1/Azure blue and MiTF as assessed in the solar lentigo group and as assessed independently in the MIS group. MiTF nuclear staining facilitated interpretation and required less laboratory preparation, as an additional counterstain was not necessary.
MiTF is as effective as MART-1/Azure blue in identifying melanocytes in the context of solar lentigo or MIS. On the basis of our results, we favor expanding the use of MiTF as an immunohistochemical marker, as it provides an efficient alternative to MART-1 with Azure blue counterstaining in the evaluation of cutaneous pigmented lesions.
皮肤色素沉着病变的评估在诊断上具有挑战性，且通常需借助免疫组织化学来辅助诊断。免疫组织化学研究通常使用3,3'-二氨基联苯胺（DAB），这会使黑素细胞和黑色素均呈棕色染色。因此，在黑色素沉着严重的病变中区分不同细胞类型可能会出现困难。天青蓝复染已与T细胞识别的黑色素瘤抗原（MART-1）联合使用，通过将黑色素染成蓝绿色来区分黑素细胞和黑色素。小眼畸形转录因子（MiTF）是一种替代免疫标志物，显示核反应性，便于解读。
利用MiTF和MART-1/天青蓝对20例日光性雀斑样痣和原位黑色素瘤（MIS）进行独立评估，以定量黑素细胞。在五个高倍视野（×400）上对黑素细胞计数求平均值，以获得平均黑素细胞计数。
在日光性雀斑样痣组以及独立评估的MIS组中，MART-1/天青蓝和MiTF评估的平均黑素细胞计数无显著差异。MiTF核染色便于解读，且所需的实验室准备较少，因为无需额外的复染。
在日光性雀斑样痣或MIS的背景下，MiTF在识别黑素细胞方面与MART-1/天青蓝同样有效。基于我们的结果，我们倾向于扩大MiTF作为免疫组织化学标志物的应用，因为在皮肤色素沉着病变的评估中，它为MART-1与天青蓝复染提供了一种有效的替代方法。
