Nonserogroup-1 Legionella pneumophila Pneumonia: Navigating Diagnostic Challenges

A 59-year-old woman with newly diagnosed immune thrombocytopenia treated with steroids and rituximab presented with a cavitary lung lesion. Extensive work-up, including bronchoalveolar lavage and transthoracic lung biopsy, were unrevealing. Molecular testing on lung tissue ultimately diagnosed nonserogroup-1 Legionella pneumophila, underscoring the utility of advanced diagnostics in clinical conundrums.