CEACAM5 and pericardial effusion: Previous reports have considered a low lymphocyte count to indicate pseudoprogression.11, 12 In contrast, pericardial effusion by immune‐related serositis showed lymphocytic predominance, without evidence of malignancy.7, 8 In our patient, the pericardial fluid contained few lymphocytes without adenocarcinoma cells; however, the bloody exudative effusion had high levels of CEA, strongly suggesting a carcinomatous nature.