Gavino Alde Carlo P, Woods Matthew T, Andea Aleodor A
Division of Dermatopathology, Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35249, USA.
Am J Dermatopathol. 2011 Oct;33(7):675-80. doi: 10.1097/DAD.0b013e31821bbfe2.
Recent studies have proposed that MART-1 may falsely stain clusters of intraepidermal nonmelanocytic cells in lichenoid dermatitides. This may become an issue especially in isolated lesions of lichen planus-like keratosis (LPLK), a condition also known as benign lichenoid keratosis, and one that is often mistaken clinically for a malignant cutaneous neoplasm. LPLKs are known to exhibit basal epidermal pseudonests, mimicking a regressing melanocytic lesion histologically, and often may prompt the pathologist to obtain a MART-1 stain. If MART-1 is falsely positive, it may seal an incorrect diagnosis. To determine whether or not pseudonests in LPLK decorated with MART-1, we reviewed 70 cases from our institution, stained them with MART-1 (Thermo Fisher-Lab Vision, Ab3 clone, 1:400 dilution, heat-induced epitope retrieval with 0.02M citrate buffer at pH 6.0), and evaluated them for the presence or absence of staining within pseudonests. Four cases demonstrated an occasional MART-1-positive junctional nest. In these cases, microphthalmia transcription factor was also positive, confirming a true melanocytic origin. None of the other cases showed a MART-1 pattern that would have been suspicious for a melanocytic lesion. We propose that this discrepancy between our study and prior ones may be explained by differences in staining protocols or by a very low incidence of non-specific staining. Our study suggests that MART-1 is a useful marker in differentiating melanocytic nests from pseudonests in LPLK.
近期研究表明，MART-1可能会错误地标记苔藓样皮炎中表皮内非黑素细胞的细胞簇。这可能会成为一个问题，尤其是在扁平苔藓样角化病（LPLK）的孤立性病变中，LPLK也被称为良性苔藓样角化病，临床上常被误诊为恶性皮肤肿瘤。已知LPLK表现出基底表皮假巢，在组织学上模仿退化的黑素细胞病变，并且常常促使病理学家进行MART-1染色。如果MART-1呈假阳性，可能会导致错误的诊断。为了确定LPLK中的假巢是否被MART-1标记，我们回顾了本机构的70例病例，用MART-1（赛默飞世尔-莱博视讯，Ab3克隆株，1:400稀释，用pH 6.0的0.02M柠檬酸盐缓冲液进行热诱导抗原修复）对其进行染色，并评估假巢内是否存在染色。4例显示偶尔有MART-1阳性的交界性巢。在这些病例中，小眼畸形转录因子也呈阳性，证实了真正的黑素细胞起源。其他病例均未显示出可疑黑素细胞病变的MART-1染色模式。我们认为，我们的研究与之前研究之间的这种差异可能是由于染色方案的不同或非特异性染色的发生率非常低所致。我们的研究表明，MART-1是区分LPLK中黑素细胞巢和假巢的有用标记物。
