Pulmonary meningioma: false-positive positron emission tomography for malignant pulmonary nodules

A case report of primary pulmonary meningioma masquerading as lung metastasis in a patient with rectal carcinoma: role of 18F-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 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.

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 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.

CONCLUSION

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.

A case of a primary pulmonary meningioma mimicking a metastasis from a papillary thyroid carcinoma due to a size reduction after radioactive iodine therapy

Background

Primary pulmonary meningiomas (PPMs) are a rare mostly benign disease presenting as a solitary pulmonary nodule and are hardly distinguishable from a metastatic tumor because of a lack of specific radiological features. We described a case of a PPM initially diagnosed as a metastatic lung tumor from thyroid cancer with a size reduction after radioactive iodine therapy.

Case presentation

A 62-year-old woman who had undergone a total thyroidectomy for a papillary thyroid carcinoma 6 years prior presented with an enlarging pulmonary nodule. The nodule had decreased in size from 7.0 to 5.5 mm after adjuvant radioactive iodine therapy and enlarged to 8.7 mm over the next 5 years. Under a clinical diagnosis of a metastatic lung tumor, she underwent a thoracoscopic pulmonary wedge resection and was pathologically diagnosed with a PPM.

Conclusion

A surgical resection is required for histological diagnoses of PPMs especially in patients with a history of a malignancy.

Computed tomography findings of primary pulmonary meningioma: A case report

RATIONALE

Primary pulmonary meningiomas are extremely rare, and only a few cases have been reported in the medical literature. Imaging findings of primary pulmonary meningiomas have been reported even more rarely.

PATIENT CONCERNS

We present the case of a 54-year-old male patient with cough and sputum lasting for 20 years. This was a case of primary pulmonary meningioma with initial suspicion of a chest wall intercostal neurinoma.

DIAGNOSES

A lung lesion was detected on chest computed tomography (CT) imaging 4 years ago. This case appeared as a solitary well-defined round nodule close to the left chest wall, with heterogeneous enhancement on CT, which inaccurately led to the suspicion of a chest wall intercostal neurinoma.

INTERVENTIONS

A thoracoscopic wedge resection was performed.

OUTCOMES

The postoperative histological diagnosis was primary pulmonary meningioma. After 2 years of follow-up, the patient is still alive without evidence of metastasis or recurrence.

LESSONS

Increased awareness of the CT characteristics of this rare tumor may broaden the radiologist's knowledge base.

Is primary pulmonary meningioma a giant form of a meningothelial-like nodule? A case report and review of the literature

Minute pulmonary meningothelial-like nodules (PMNs) are asymptomatic, small nodules that are occasionally detected in surgical or autopsy specimens. Recent improvements in tumor imaging and the increased use of computed tomography (CT) scans of the chest have led to the early detection of these pulmonary nodules in various clinical settings, often before surgery or health examinations. However, large PMNs have rarely been observed. In this study, we report a patient with a large PMN, which was almost identical to so-called ‘primary pulmonary meningioma’. A CT scan of his chest revealed a small, well-circumscribed nodule. Immunohistochemical analysis of the tumor revealed that the tumor cells were positive for CD56, epithelial membrane antigen, and progesterone receptor. Given the similarity of these results to the staining pattern of minute PMNs in previous reports, we suggest that the primary pulmonary meningiomas reported to date are, in fact, a giant form of PMN.