Introduction Metastatic melanoma (MM) is an uncommon finding in serous effusion specimens with a highly variable cytomorphology. Methods We reviewed specimens submitted over a 19-year period to determine (a) the range of cytologic findings in effusion specimens from melanoma patients and b) the cytologic presentation and immunoprofile of MM in effusion specimens. Results Of 123 serous effusion specimens from patients with clinical notes of melanoma, 59% were reported negative for malignancy; 16% were reported with a non-melanoma malignancy; 19% MM; and 6% atypical, MM not excluded. Pleural fluids were twice as likely to be reported as MM than peritoneal samples. Review of 44 cases with confirmed MM showed the most common cytologic pattern was epithelioid. Most (88%) cases contained mainly dispersed plasmacytoid cells, but many (61%) also contained malignant cells arranged in loose groups. Rare cases also had spindle cells, giant bizarre cells, small lymphoid-like cells or cells with large hard-edged vacuoles, mimicking other metastatic malignancies. MM cases containing predominantly plasmacytoid cells often mimicked reactive mesothelial cells. As well as being composed of cells of similar size, features such as bi- and multi-nucleation, round nuclei, mild anisokaryosis, nucleoli and loose groups were common to both. Features seen more commonly in MM than reactive cells included large nucleoli (95%) and intranuclear cytoplasmic inclusions (41%), binucleate ‘bug-eyed demons’, and small punctate vacuoles on the air-dried preparations. Pigment was identified in 36% of cases. IHC is a valuable aid in confirming the cell type. The sensitivity for the most commonly used melanoma markers was: S100 84% (21/25); pan-Melanoma 100% (19/19); HMB45 92% (11/12); Melan A 92% (11/12); SOX10 91% (10/11). No staining was reported for Calretinin (0/21); AE1/AE3 (0/11); EMA (0/16); Ber-Ep4 (0/13). Discussion: Effusion specimens from patients with a history of melanoma are frequently (40%) malignant, but almost as likely to be reported as a non-melanoma malignancy as MM. The cytology of MM may mimic a wide range of other metastatic malignancies, but also often closely resemble reactive mesothelial cells. It is important to be aware of this latter pattern so that IHC markers can be applied.


中文翻译：

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黑色素瘤患者浆液渗出标本的细胞学发现。

简介 转移性黑色素瘤 (MM) 是一种罕见的浆液性渗出液标本，具有高度可变的细胞形态。方法 我们回顾了 19 年期间提交的标本，以确定 (a) 黑色素瘤患者的渗出标本中细胞学检查结果的范围，以及 b) 渗出标本中 MM 的细胞学表现和免疫特征。结果 在来自有黑色素瘤临床记录的患者的 123 份浆液性积液标本中，59% 的恶性肿瘤呈阴性；据报告，16% 患有非黑色素瘤恶性肿瘤；19% MM；6%非典型，MM不排除。胸腔积液被报告为 MM 的可能性是腹膜样本的两倍。对 44 例确诊 MM 病例的回顾显示，最常见的细胞学模式是上皮样。大多数（88%）病例主要含有分散的浆细胞样细胞，但许多（61%）还含有排列松散的恶性细胞。极少数病例还存在梭形细胞、巨大奇异细胞、小淋巴样细胞或具有大硬边空泡的细胞，类似于其他转移性恶性肿瘤。主要含有浆细胞样细胞的多发性骨髓瘤病例通常模仿反应性间皮细胞。除了由大小相似的细胞组成外，两者都具有双核和多核、圆形核、轻度异核、核仁和松散团等特征。与反应性细胞相比，MM 中更常见的特征包括大核仁 (95%) 和核内细胞质内含物 (41%)、双核“虫眼恶魔”和风干制剂上的小点状空泡。36% 的病例中发现了色素。IHC 对于确认细胞类型非常有用。最常用的黑色素瘤标记物的敏感性为：S100 84% (21/25)；泛黑色素瘤 100% (19/19)；HMB45 92% (11/12); 梅兰 A 92% (11/12); SOX10 91% (10/11)。未报告钙视网膜蛋白染色 (0/21)；AE1/AE3 (0/11)；指数移动平均线 (0/16)；Ber-Ep4 (0/13)。讨论：有黑色素瘤病史的患者的积液标本经常 (40%) 是恶性的，但几乎与 MM 一样被报告为非黑色素瘤恶性肿瘤。MM 的细胞学可能模仿多种其他转移性恶性肿瘤，但也常常与反应性间皮细胞非常相似。重要的是要了解后一种模式，以便应用 IHC 标记。