{"id":45095,"date":"2025-08-05T14:04:40","date_gmt":"2025-08-05T06:04:40","guid":{"rendered":"https:\/\/medicine.nus.edu.sg\/pathweb\/?page_id=45095"},"modified":"2025-08-05T17:04:03","modified_gmt":"2025-08-05T09:04:03","slug":"bcf-1","status":"publish","type":"page","link":"https:\/\/medicine.nus.edu.sg\/pathweb\/cytopath\/cyto-mystery-cases\/bcf-1\/","title":{"rendered":"Mystery cases &#8211; Body Cavity Fluids 1"},"content":{"rendered":"\n<h2>\n\t\tBody Cavity Fluids 1\n\t<\/h2>\n\t<h1>A tricky pleural fluid<\/h1>\n\t<p><strong>Clinical history<\/strong>: A 72-year-old man with shortness of breath is found to have a pleural effusion. Lung imaging shows consolidation in the ipsilateral lung. A pleural fluid cytology sample is taken, and a cell block processed.\u00a0<\/p>\n\t\t\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/medicine.nus.edu.sg\/pathweb\/wp-content\/uploads\/2025\/06\/fluid.png\" alt=\"Body Cavity Fluids case 1\" itemprop=\"image\" height=\"847\" width=\"1129\" title=\"fluid\" onerror=\"this.style.display='none'\"  \/>\n\t\t\t\t\t<a href=\"#\" id=\"fl-accordion--label-0\" tabindex=\"0\" aria-controls=\"fl-accordion--panel-0\">Immunohistochemistry<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"#\" id=\"fl-accordion--icon-0\" tabindex=\"-1\"><i title=\"Expand\">Expand<\/i><\/a>\n\t\t\t\t\t<p>&nbsp;<\/p>\n<table>\n<tbody>\n<tr>\n<td><img decoding=\"async\" src=\"https:\/\/medicine.nus.edu.sg\/pathweb\/wp-content\/uploads\/2025\/06\/fluid-2.png\" alt=\"\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The cells with signet ring morphology are negative for the epithelial marker EP4 and the mesothelial marker WT1. A small group of WT1-positive mesothelial cells is seen. CD163 highlights numerous cells with signet ring cell morphology.<\/p>\n<p>In body cavity fluid samples, the differential diagnoses for cells with signet ring morphology include:<\/p>\n<ul>\n<li>Metastatic adenocarcinoma with signet ring cell morphology<\/li>\n<li>Macrophages<\/li>\n<li>Mesothelial cells<\/li>\n<\/ul>\n<p>The most helpful morphological features are the nuclei &#8211; significant nuclear abnormalities can be seen in adenocarcinoma (hyperchromatic or irregular nuclei with prominent nucleoli) as well as the nature of the cytoplasm (finely bubbly, pinkish in alcohol-stained smears, or containing a small mucin droplet in adenocarcinoma). When the cells contain water as a result of degenerative changes (e.g. in macrophages and mesothelial cells), the vacuole appears clear and empty as seen in this case.<\/p>\n<p>A panel of immunostains will provide the answer as shown above.<\/p>\n\t\t\t\t\t<a href=\"#\" id=\"fl-accordion--label-1\" tabindex=\"0\" aria-controls=\"fl-accordion--panel-1\">Diagnosis<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"#\" id=\"fl-accordion--icon-1\" tabindex=\"-1\"><i title=\"Expand\">Expand<\/i><\/a>\n\t\t\t\t\t<p>&nbsp;<\/p>\n<table>\n<tbody>\n<tr>\n<td><img decoding=\"async\" src=\"https:\/\/medicine.nus.edu.sg\/pathweb\/wp-content\/uploads\/2025\/06\/fluid-3.png\" alt=\"\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The diagnosis is <strong>negative: No malignant cells seen<\/strong>. The cells with signet ring morphology are macrophages (CD163-positive, EP4- and WT1-negative). Picture 1 shows the Case of the Month, while picture 2 shows the cell block of a signet ring cell adenocarcinoma. Compare the nuclear and cytoplasmic features.\u00a0\u00a0<\/p>\n\t<p><em>Case writer: Dr Noel Chia<\/em><\/p>\n\n","protected":false},"excerpt":{"rendered":"<p>Body Cavity Fluids 1 A tricky pleural fluid Clinical history: A 72-year-old man with shortness of breath is found to have a pleural effusion. Lung imaging shows consolidation in the ipsilateral lung. A pleural fluid cytology sample is taken, and a cell block processed.\u00a0 Immunohistochemistry Expand &nbsp; The cells with signet ring morphology are negative [&hellip;]<\/p>\n","protected":false},"author":828,"featured_media":0,"parent":44933,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-45095","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>NUS Pathweb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/medicine.nus.edu.sg\/pathweb\/cytopath\/cyto-mystery-cases\/bcf-1\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:description\" content=\"Body Cavity Fluids 1 A tricky pleural fluid Clinical history: A 72-year-old man with shortness of breath is found to have a pleural effusion. 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