Whorls in the Lung: A Case of Primary Pulmonary Meningioma

A primary pulmonary meningioma (PPM) is an exceptionally rare, usually benign tumour, with only about 50 cases reported worldwide. We describe a 75-year-old Japanese female patient with a strong family history of gastrointestinal malignancy, in whom a solitary upper-lobe pulmonary nodule was incidentally detected. Radiological evaluation, including Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET), suggested malignancy, but wedge resection and histopathological assessment, supported by immunohistochemistry, confirmed PPM. This case highlights the diagnostic challenge of distinguishing PPM from primary lung carcinoma, reinforces the importance of tissue confirmation and exclusion of intracranial disease, and draws attention to the potential role of genetic or environmental factors in its pathogenesis. By documenting a well-characterized case with an atypical upper-lobe location, this report contributes practical insights for clinicians and pathologists in the diagnosis and management of PPM.