A diagnostic conundrum in the context of a pandemic of Coronavirus Disease 2019 (COVID-19)

A 52-year-old with lung cancer and brain metastases, on a 3-month weaning regime of dexamethasone, had a coincidental finding of bilateral, patchy ground-glass opacifications of both central and peripheral lung fields on computed tomography (CT). This was reported to be a sign of Coronavirus Disease 2019 (COVID-19). On Day 13, due to poor clinical progression and multiple negative reverse transcriptase-polymerase chain reaction tests for COVID-19, an alternative diagnosis was sought. Subsequently, this led to a diagnosis of Pneumocystis jirovecii pneumonia. This case demonstrates complicating factors in the diagnosis of COVID-19 and the presence of cognitive bias during a pandemic, which may lead clinicians to overlook a diagnosis, which may otherwise be addressed earlier.