When Positron Emission Tomography (PET) Is Misleading: Ion™ Robotic Bronchoscopy Identifies Organizing Pneumonia and Unmasks a Rare Pulmonary Granular Cell Tumor.

Pulmonary nodules with increased metabolic activity on positron emission tomography (PET) are frequently presumed malignant; however, inflammatory and rare benign neoplastic processes may produce false-positive findings. A 61-year-old African American male with a history of calcified and non-calcified pulmonary nodules and severe emphysema was referred to our pulmonary nodule clinic from the emergency department after a newly discovered lung nodule was identified on computed tomography (CT) of the chest. Subsequent evaluation demonstrated metabolic activity on PET, raising concern for malignancy; however, tissue diagnosis revealed organizing pneumonia. This case highlights diagnostic pitfalls associated with commonly used imaging and biomarker modalities in the evaluation of pulmonary nodules and emphasizes the importance of clinical awareness of a rare tumor, granular cell tumor (GCT), among physicians who may be unfamiliar with or have never encountered this condition.