A case report of primary pulmonary meningioma masquerading as lung metastasis in a patient with rectal carcinoma: role of (18)F-FDG PET/CT

BACKGROUND: Primary pulmonary meningioma (PPM) is an extremely rare disease, which is often misdiagnosed as lung metastasis. Previous studies indicated that PPM usually showed homogeneous enhancement on enhanced CT and high uptake of (18)F-fluorodeoxyglucose ((18)F-FDG) on positron emission tomography/CT (PET/CT). In this study, we report a case of PPM with atypical enhanced CT and (18)F-FDG PET/CT features in a patient with rectal carcinoma. CASE PRESENTATION: A 70-year-old male was demonstrated to have rectal carcinoma by biopsy while a solitary pulmonary nodule (SPN) with well-defined edges measuring 13 × 13 × 15 mm was almost simultaneously found in the right lower robe on chest CT scan. Contrast-enhanced CT and PET/CT revealed mild centripetal enhancement of the nodule without accumulation of (18)F-FDG. A thoracoscopic wedge resection of the right lower lobe was finally performed and histopathologic examinations and PET/CT imaging showed that the nodule was a PPM. CONCLUSION: PPM is a rare disease with heterogeneity not only in blood supply but also in glucose metabolism. (18)F-FDG PET/CT may be an effective method for differentiating benign and malignant SPNs. The diagnosis of PPM depends on pathological and radiological examinations.