Quezado M M, Abati A D, Albuquerque A V, Wilson J, Merino M J, Filie A C
Cytopathology Section, Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Mod Pathol. 1998 Oct;11(10):1010-5.
Malignant melanoma (MM) can mimic soft tissue (ST) and epithelial neoplasms. An immunoperoxidase (IP) panel and a morphologic comparison of the primary are used in diagnosis, which can be difficult when the morphologic and IP profiles of a metastatic lesion simulate those of an ST neoplasm. Through the comparison of known genetic abnormalities in primary and metastatic neoplasms, a definitive diagnosis can be suggested on the basis of the finding of identical allelic losses through the use of microdissection (MD) and the polymerase chain reaction (PCR). Genetic alterations involving the p16 gene on chromosome 9p21 have been observed in MM. We present the case of a 56-year-old man with known MM in whom multiple metastatic lesions to the skin and an adrenal gland developed during a 5-year period. A fine-needle aspiration (FNA) of a new ST buttock lesion was performed; the specimen had cytologic features different from those of the primary neoplasm and simulated a possible primary ST neoplasm. We attempted to make a definitive diagnosis of MM in the FNA of the ST buttock lesion through a genetic comparison with the primary neoplasm as well as with the other metastatic sites. Direct-visualization MD was performed on histologic glass slides of the primary and adjacent tissue (normal control), and the metastatic lesions, along with malignant cell clusters from the buttock lesion FNA. DNA was extracted and PCR amplified with primers D9S171 and IFNA for the p16 locus at the 9p21-22 region. Loss of heterozygosity for the D9S171 marker at the p16 gene locus was identified in all of the neoplastic tissue tested. Normal skin elements did not show deletion. The combination of MD and PCR are powerful tools that can be used for the comparison of genetic abnormalities in primary and metastatic neoplasms with unusual morphologic features to help support a diagnosis with a noncontributory IP.
恶性黑色素瘤（MM）可模仿软组织（ST）和上皮性肿瘤。诊断时需使用免疫过氧化物酶（IP）检测组合以及对原发灶进行形态学比较，而当转移灶的形态学和IP特征与ST肿瘤相似时，诊断可能会很困难。通过比较原发肿瘤和转移肿瘤中已知的基因异常情况，利用显微切割（MD）和聚合酶链反应（PCR）发现相同的等位基因缺失，从而做出明确诊断。在MM中已观察到涉及9号染色体p21上p16基因的基因改变。我们报告了一例56岁已知患有MM的男性病例，该患者在5年期间出现了多处皮肤和肾上腺转移灶。对一个新出现的ST臀部病灶进行了细针穿刺抽吸（FNA）；标本的细胞学特征与原发肿瘤不同，类似可能的原发性ST肿瘤。我们试图通过与原发肿瘤以及其他转移部位进行基因比较，在ST臀部病灶的FNA中做出MM的明确诊断。对原发灶和相邻组织（正常对照）以及转移灶的组织学玻片进行直视下MD，同时对来自臀部病灶FNA的恶性细胞簇也进行MD。提取DNA并用针对9p21 - 22区域p16位点的引物D9S171和IFNA进行PCR扩增。在所检测的所有肿瘤组织中均发现p16基因位点的D9S171标记杂合性缺失。正常皮肤组织未显示缺失。MD和PCR相结合是强大的工具，可用于比较具有不寻常形态学特征的原发肿瘤和转移肿瘤中的基因异常，以帮助支持在IP检测无诊断价值时做出诊断。
