Ferrão, JSardinha, MDutra, E2023-08-112023-08-112021-08Am J Med Sci . 2021 Aug;362(2):211-214http://hdl.handle.net/10400.17/4641Hematological paraneoplastic syndromes are fairly uncommon. While mild leukocytosis in solid tumors is well reported, white blood cell (WBC) count over 50,000 u/L, described as paraneoplastic leukemoid reaction (PLR), is not. Indeed, when found, it is usually associated with a higher burden of disease, tumor activity and worse clinical outcomes. We report the case of a challenging and burdensome diagnosis of a presumptive hematological paraneoplastic syndrome in a patient with a locally advanced lung cancer admitted in the Internal Medicine ward. After the end of chemotherapy, clinical and laboratory benefit was observed; however, the aggressive course of the disease became clear, with progression and downhill course that was unresponsive to treatment.engCHLC MEDHSAC ONCCHLC ANPATAntineoplastic Agents / therapeutic useCarcinoma / complications*Carcinoma / drug therapyFatal OutcomeHumansMaleMiddle AgedLung Neoplasms / complications*Lung Neoplasms / drug therapyParaneoplastic Syndromes / diagnosis*Paraneoplastic Syndromes / pathology*Prognosisjournal article10.1016/j.amjms.2021.01.027