Key clinical message: EDTA-dependent pseudothrombocytopenia as well as myelosuppression should be suspected when thrombocytopenia occurs in patients with autoimmune disease during chemotherapy.
Abstract: A patient with pancreatic cancer and ulcerative colitis developed transient ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia with exacerbation of ulcerative colitis during chemotherapy. Unfortunately, pseudothrombocytopenia could not be immediately detected because thrombocytopenia was masked by a reasonable time course of adverse events associated with chemotherapy and ulcerative colitis recurrence. When thrombocytopenia occurs during chemotherapy, especially in patients with autoimmune diseases, EDTA-dependent pseudothrombocytopenia and bone marrow suppression caused by anti-cancer agents should be suspected.
Keywords: autoimmune disease; delayed treatment; laboratory artifact; misleading diagnosis; transient EDTA‐dependent pseudothrombocytopenia.
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