癌细胞增多症是指外周血中存在循环肿瘤细胞，当癌细胞存在量极少时，很难检测到。我们描述了一名 56 岁患者的病例，该患者出现弥散性血管内凝血 (DIC) 和多器官衰竭。尽管最初怀疑败血症，但外周血涂片显示存在非典型细胞，主要位于羽状边缘，导致推定诊断为原发性不明的癌细胞增多症。我们的血液分析仪 (Sysmex XN-9100) 检测到高荧光细胞群的存在，并用全细胞角蛋白 AE1/AE3 进行免疫组织化学染色，证实了癌细胞的起源。患者转诊至我院后 4 天死亡。尸检发现多形性小叶乳腺癌（三阴性，雄激素受体阴性）。鉴于癌细胞增多症患者的临床敏锐度，早期诊断对于指导治疗至关重要。该案例强调了依靠复杂的标记算法和增强的数字成像来优化当前工作流程的重要性，以帮助及早发现这种罕见的情况。当患者出现来源不明的 DIC 且血液分析仪检测到高荧光信号时，应通过广泛的外周血显微镜检查积极排除癌细胞增多症。© 作者 2024。由牛津大学出版社代表美国学会出版用于临床病理学。版权所有。如需商业重复使用，请联系 reprints@oup.com 获取转载和转载的翻译权。所有其他权限均可通过我们网站文章页面上的“权限”链接通过我们的 RightsLink 服务获得 - 如需了解更多信息，请联系journals.permissions@oup.com。

Carcinocythemia, known as the presence of circulating tumor cells in the peripheral blood, is difficult to detect when the carcinoma cells are minimally present. We describe a case of a 56-year-old patient presenting with disseminated intravascular coagulation (DIC) and multiple organ failure. Despite initial suspicion of sepsis, a peripheral blood smear showed the presence of atypical cells, mainly located at the feathered edge, leading to a presumptive diagnosis of carcinocythemia of unknown primary origin. The presence of a high-fluorescent cell population detected by our hematology analyzer (Sysmex XN-9100) and immunohistochemical staining with pancytokeratin AE1/AE3 confirmed the carcinoma cell origin. The patient died 4 days after referral to our hospital. Postmortem examination revealed a pleomorphic lobular breast carcinoma (triple-negative, androgen receptor-negative). Given the clinical acuity of patients with carcinocythemia, early diagnosis is essential to guide management. This case underscores the importance of optimizing current workflows relying on complex flagging algorithms and enhanced digital imaging to aid in the early detection of such rare condition. When patients present with DIC of unknown origin and high fluorescent signals are detected on the hematology analyzer, carcinocythemia should actively be ruled out by extensive microscopic peripheral blood examination.© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.