BACKGROUND A case of peritoneal mesothelioma with an anaplastic lymphoma kinase (ALK) translocation was identified, and we conducted further studies to obtain diagnostic and therapeutic insights. We believe that this is the first report describing the cytology of this new tumor type. CASE A teenage woman was referred for severe pleural effusion. Enhanced computed tomography indicated an abdominal mass with ascites. Laparoscopy revealed tumor dissemination from the pelvis to the upper abdomen. Because a high-grade serous carcinoma was suspected, ascitic cytology and biopsy were performed. Cytologically, the tumor displayed characteristics of both adenocarcinoma and reactive or neoplastic mesothelial cells. After extensive pathological evaluation, the tumor was diagnosed as malignant peritoneal mesothelioma. To verify the diagnosis and aid in developing a therapeutic strategy, several companion diagnostics were tried. Surprisingly, the tumor was ALK-positive, and ALK recombination was confirmed by an ALK break-apart test. Retrospectively, cells and tissue specimens were stained with ALK intercalated antibody-enhanced polymer. Tumor cells were clearly distinguished from the nonneoplastic background. Recombination in ALK was reconfirmed by the National Cancer Center Japan, and the patient was enrolled in a clinical trial for alectinib. CONCLUSION Companion diagnostics-based cytology may provide a useful means of monitoring and evaluating a molecular-targeted therapy.

中文翻译：

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通过伴侣诊断检测腹水间变性淋巴瘤激酶重排的间皮瘤细胞。

背景鉴定了一例间变性淋巴瘤激酶（ALK）易位的腹膜间皮瘤，我们进行了进一步的研究以获得诊断和治疗方面的见识。我们相信，这是描述这种新型肿瘤细胞学的第一份报告。案例一名青少年妇女因严重胸腔积液而被转诊。增强型计算机断层扫描显示腹部有腹水。腹腔镜检查显示肿瘤从骨盆扩散到上腹部。由于怀疑是高度浆液性癌，因此进行了腹水细胞学检查和活检。在细胞学上，该肿瘤表现出腺癌和反应性或赘生性间皮细胞的特征。经过广泛的病理评估，该肿瘤被诊断为恶性腹膜间皮瘤。为了验证诊断并帮助制定治疗策略，尝试了几种辅助诊断方法。令人惊讶的是，该肿瘤是ALK阳性的，并且通过ALK断裂试验证实了ALK重组。回顾性地，将细胞和组织标本用ALK嵌入抗体增强的聚合物染色。肿瘤细胞与非肿瘤性背景有明显区别。日本国家癌症中心再次确认了ALK的重组作用，并将该患者纳入了alectinib的临床试验。结论基于伴侣诊断的细胞学可能提供监测和评估分子靶向治疗的有用手段。回顾性地，将细胞和组织标本用ALK嵌入抗体增强的聚合物染色。肿瘤细胞与非肿瘤性背景有明显区别。日本国家癌症中心再次确认了ALK的重组作用，并将该患者纳入了alectinib的临床试验。结论基于伴侣诊断的细胞学可能提供监测和评估分子靶向治疗的有用手段。回顾性地，将细胞和组织标本用ALK嵌入抗体增强的聚合物染色。肿瘤细胞与非肿瘤性背景有明显区别。日本国家癌症中心再次确认了ALK的重组作用，并将该患者纳入了alectinib的临床试验。结论基于伴侣诊断的细胞学可能提供监测和评估分子靶向治疗的有用手段。