BACKGROUND: A primary pulmonary meningioma is an extremely rare entity. Primary pulmonary meningiomas manifested with a ground glass nodule are a very rare occurrence in clinical practice.
METHODS: In this study, we report a case of a primary pulmonary meningioma with atypical computed tomography features. A 59-year-old Han Chinese female came to our hospital for treatment and reported that her physical examination revealed a ground glass nodule in the right lung for over 3 months. The histologic result revealed a primary pulmonary meningioma. The patient underwent a thoracoscopic lung wedge resection of the right upper lobe for a ground glass nodule. After 1 year of follow-up, the patient is still alive without evidence of metastasis or recurrence.
CONCLUSIONS: Primary pulmonary meningiomas could have a variety of radiological findings. As there are no specific radiologic features for the diagnosis of primary pulmonary meningiomas, complete resection of the lesion is required for both diagnosis and treatment. It is necessary to note the imaging features of primary pulmonary meningiomas, presenting as a ground glass nodule; this rare tumor should be considered in differential diagnoses.

BACKGROUND: Primary pulmonary meningioma (PPM) is an exceedingly rare neoplasm originating in the meninges within the lung. Despite sharing similarities with its central nervous system (CNS) counterparts, PPM presents unique diagnostic challenges and therapeutic considerations owing to its infrequent occurrence.
METHODS: This case report describes a 73-year-old male who underwent chest computed tomography (CT), which revealed a mass in the posterior basal segment of the right lower lobe, suggestive of a low-grade malignant tumor approximately 30-40 mm in size. Single-port video-assisted thoracoscopic surgery (VATS) was performed to resect the mass via localized lesion excision (lung wedge resection). Intraoperative frozen section pathology indicated a low-grade malignant epithelial tumor, leading to a decision for maximal lung function preservation, considering the patient\'s advanced age. The surgical team opted for a localized excision to ensure negative margins. Histopathological analysis confirmed the diagnosis of epithelioid PPM, a rare subtype even among PPM cases (World Health Organization [WHO] Grade I). The patient was discharged 9 days after surgery without complications and resumed normal daily activities 1 month postoperatively. The rarity of PPM precludes a standardized treatment protocol, with surgical resection as the primary approach. However, the efficacy of adjunctive therapies remains uncertain due to limited evidence.
CONCLUSIONS: This case report contributes to a better understanding of PPM and emphasizes the importance of a comprehensive diagnostic evaluation and individualized treatment planning for this rare entity.

In this editorial, we comment on an article by Ruan et al published in a recent issue of the World Journal of Clinical Case. Pulmonary meningothelial proliferative lesions, including primary pulmonary meningiomas, minute pulmonary meningothelial-like nodules, and metastatic pulmonary meningiomas are rare pulmonary lesions. These lesions are difficult to differentiate from lung cancers based on clinical and imaging manifestations. Herein, we briefly introduce the clinical, imaging, and pathological characteristics of these lesions and discuss their pathogenesis to strengthen the current understanding of pulmonary meningothelial proliferative lesions in clinical diagnosis and therapy.

Primary pulmonary meningiomas (PPMs) are rare meningothelial proliferation that lacks characteristic imaging findings, making their distinction from other peripheral lung tumors challenging. Therefore, surgical resection is often performed for the diagnosis and treatment of PPM. Herein, we describe a surgical case of PPM that grew over 10 years. A 63-year-old woman was referred to our department due to right middle lobe lung tumor enlargement. No significant symptoms were observed. Chest computed tomography revealed a tumor in the middle lobe of the right lung. F-18 fluorodeoxyglucose positron emission tomography showed accumulation in the nodule; thus, lung cancer could not be ruled out. Therefore, the preoperative differential diagnosis was cStageIB lung cancer. A right middle lobectomy was performed, and a histopathology examination revealed meningioma. There were no primary lesions in the head and whole spine magnetic resonance imaging, thus, a final diagnosis of PPM was made. Cautious observation is required postoperatively due to the possibility of recurrence.

Primary pulmonary meningioma is a rare benign tumor usually presenting as a solitary pulmonary nodule or mass. It can be easily misinterpreted as a primary lung tumor or metastases on imaging studies. We present a 54-year-old woman with an incidentally discovered solitary lung nodule, which was diagnosed as metaplastic primary pulmonary meningioma following resection. Metaplastic meningioma is a rare WHO grade 1 meningioma subtype with focal or global mesenchymal differentiation. To the authors\' knowledge, primary pulmonary meningioma with mesenchymal differentiation has not been described previously in the English literature.

Meningioma is a common benign tumor originating in the brain, but primary pulmonary meningioma is very rare. It is usually benign, slow-growing, and responds well to treatment. The most common manifestation is an isolated pulmonary nodule that radiologically resembles a benign primary lung tumor. Herein, we report a case of a complete thoracoscopic resection of a primary pulmonary meningioma.

BACKGROUND: An ectopic meningioma, such as a primary pulmonary meningioma (PPM), is a rare type of tumor that primarily originates outside of the central nervous system. The most common presentation of PPM is isolated pulmonary nodules or masses, and most of them are benign. Only sporadic cases have been reported. This case reported a giant primary pulmonary meningioma and systematically reviewed previously reported cases in the literature.
METHODS: A 55-year-old female suffered from asthma after activity, chest tightness, and a persistent dry cough for 2 months. Chest computed tomography (CT) showed a huge mass with calcification in the left lower lobe. And positron emission tomography (PET)/CT revealed mild FDG accumulation of the mass. The mass was finally surgically removed and PPM was confirmed according to histopathologic examinations.
CONCLUSIONS: PPM is a rare disease with heterogeneity not only in CT features but also in glucose metabolism. FDG uptake levels do not identify benign from malignant, benign PPM may have high FDG uptake and malignant may have low.

Primary pulmonary meningioma (PPM) is a rare and benign slow growing tumor with good prognosis. It often presents as an asymptomatic, well-circumscribed, solitary pulmonary nodule. Wedge resection is the management of choice for both diagnosis and treatment. Here, we report one case of PPM with increased fluorodeoxyglucose (FDG) uptake and associated micronodules, which was clinically suspicious for malignancy. The patient was a 60-year-old female who presented with persistent shortness of breath for 1 year. Chest computed tomography showed a 1.5-cm well-circumscribed homogenous nodule in the left upper lobe with increased FDG uptake and multiple smaller well-circumscribed micronodules scattered in both lungs. Left upper lobe wedge resection confirmed the diagnosis of PPM. PPM can deceptively mimic malignancy, so recognizing this rare entity and including it in the differential diagnoses of pulmonary nodules, especially with avid uptake of FDG, is crucial to avoid misdiagnosis and overtreatment.

BACKGROUND: Primary pulmonary meningioma (PPM) is a rare disease that is usually benign. The most common presentation of PPM is isolated pulmonary nodules or masses, so the disease can mimic any other lung tumor on imaging, especially lung cancer or metastasis.
METHODS: A 47-year-old asymptomatic woman presented with a well-defined, lobulated pulmonary mass with calcification in the left lower lobe. The mass measured 69 mm × 57 mm × 61 mm and was found during a chest computed tomography (CT) performed for physical examination. Contrast-enhanced CT and positron emission tomography (PET)/CT revealed mild enhancement of the mass, with accumulation of 18-fluoro-2-deoxy-D-glucose (18F-FDG). Transbronchial biopsy suggested a provisional diagnosis of low-grade neuroendocrine tumor. Subsequent enhanced head magnetic resonance imaging revealed no positive lesions. An open cuff resection of the left lower lobe and wedge resection of the lingual segment were performed. Histopathological and immunohistochemical examination revealed that the mass was a PPM.
CONCLUSIONS: PPM should be considered in the differential diagnosis of isolated pulmonary masses found incidentally on CT and should be diagnosed based on a combination of radiological and histological features. Surgical resection is currently the main treatment strategy. No recurrence of benign PPMs has been reported after complete resection.

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 18F-fluorodeoxyglucose (18F-FDG) on positron emission tomography/CT (PET/CT). In this study, we report a case of PPM with atypical enhanced CT and 18F-FDG PET/CT features in a patient with rectal carcinoma.
METHODS: 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 18F-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.
CONCLUSIONS: PPM is a rare disease with heterogeneity not only in blood supply but also in glucose metabolism. 18F-FDG PET/CT may be an effective method for differentiating benign and malignant SPNs. The diagnosis of PPM depends on pathological and radiological examinations.