Primary pulmonary meningioma: A rare case report of aspiration cytological features and immunohistochemical assessment

Incidental Metaplastic Primary Pulmonary Meningioma

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.

Rapid growth of primary pulmonary meningioma with hemoptysis

While lung cancer is the predominant neoplasm causing hemoptysis, rare benign neoplasms can also be associated with hemoptysis. A 60-year-old woman presented with cough and hemoptysis. Chest computed tomography revealed an oval-shaped, well-circumscribed solitary mass (10 cm in size) in the right lower lobe, which had grown rapidly over the past year. The presence of intramass air bubbles and a surrounding halo of ground-glass opacities suggested the hemorrhagic rupture of a circumscribed hematoma into the surrounding lung tissue. Subsequent right lower lobectomy revealed a well-demarcated hematoma; its wall consisted of nonatypical spindle tumor cells, which were histologically diagnosed as meningioma. No meningioma was observed in the central nervous system, leading to the diagnosis of primary pulmonary meningioma. This case highlights PPM as a rare benign tumor (World Health Organization grade 1) capable of rapid development due to intratumoral hemorrhage, presenting with hemoptysis.

Primary pulmonary meningioma and minute pulmonary meningothelial-like nodules: Rare pulmonary nodular lesions requiring more awareness in clinical practice

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 ectopic meningioma in the thoracic cavity: A rare case report and review of the literature

Background

Meningioma is a common type of intracranial tumor in adults. It rarely arises in the chest, with only a few case reports in the English literature. Here, we report the case of a patient with a primary ectopic meningioma (PEM) located in the thoracic cavity.

Case presentation

A 55-year-old woman presented with exercise-induced asthma, chest tightness, intermittent dry cough and fatigue for several months. Computed tomography revealed the presence of a huge mass in the thoracic cavity, with no connection to the spinal canal. Lung cancer and mesothelioma were suspected, and surgery was performed. Grossly, the mass was a grayish-white solid 9.5 cm × 8.4 cm × 5.3 cm in size. The microscopic morphology of the lesion was consistent with that of typical central nervous system meningioma. The pathological subtype was transitional meningioma. The tumor cells were arranged in a fascicular, whorled, storiform and meningithelial pattern, with occasional intranuclear pseudo-inclusions and psammoma bodies. In focal areas tumor cells were considerably dense, and the cells were round or irregular in shape, with less cytoplasm, uniform nuclear chromatin, and visible nucleoli and mitoses (2/10 HPF). By immunohistochemistry, the neoplastic cells showed strong and diffuse staining with vimentin, epithelial membrane antigen and SSTR2 with variable expression of PR, ALK and S100 protein. However, the cells were negative for GFAP, SOX-10, inhibin, CD34, STAT6, smooth muscle actin, desmin, CKpan, D2-40, WT-1, CK5/6 and CD45. The highest proliferation index by Ki-67 was 15%. The abnormal expression of ALK led to the initial misdiagnosis of an inflammatory myofibroblastic tumor. After 12 months of follow-up, no disease progression was observed.

Conclusion

The presence of primary ectopic meningiomas in the thoracic cavity is extremely rare, and this tumor is easily misdiagnosed clinically. Imaging is suggested to determine the location and possible differential diagnosis, while the final diagnosis should be via pathological examination. Immunohistochemistry is crucial for disease diagnosis. Owing to our limited knowledge of PEM, its pathogenesis and tissue of origin remain unclear. Clinicians should pay close attention to such potential patients. The present case report may provide insights into the diagnosis and therapy of patients with this tumor.

Minute pulmonary meningothelial-like nodules: associations between computed tomography and pathology features

Background

Increased use of multislice computed tomography (CT) scans has revealed that minute pulmonary meningothelial-like nodules (MPMNs) showed as ground-glass nodules (GGNs) are frequent in patients. However, little is known about the incidence and fate of nodules. By using a cross-sectional design, this study compared the multislice CT signs and pathological results of MPMNs, and further used pathological results to explain the formation mechanism of the CT signs of MPMNs to improve the clinical understanding of the disease.

Methods

The clinicopathological data of 93 cases diagnosed as MPMNs in the Jiangsu Province Hospital from January 2016 to September 2019 and the Nanjing First Hospital from January 2017 to December 2019 were examined. The related literature was reviewed, and each case's age, gender, medical history, and preoperative CT examinations were classified. Based on CT signs, this study analyzed the imaging features, including size, shape, boundary, distribution, opacity, and their relationship with pulmonary blood vessels.

Results

A total of 13 cases had immunohistochemistry results among which the lesions showed consistent positive expression of vimentin (100%), followed by epithelial cell membrane antigen (92.3%) and progesterone (8%). The MPMNs mainly occurred in individuals aged 50-59 years (32.6%). Most patients (82.6%) had neoplastic disease. All nodules (100%) manifested with a round shape and well-demarcated borders on images. The size of the nodules on CT scans ranged from 2.5 to 5.0 mm, with an average size of 3.04±1.12 mm. Most nodules were subpleural (89.1%) and showed ground-glass opacity (97.8%). The follow-up results of postoperative clinical manifestations and chest CT examination were negative in 12 patients.

Conclusions

This study suggested that the pathological findings of MPMNs could explain the formation mechanism of the CT signs. The results can provide guidance for the diagnosis of the disease in the future.

Primary ectopic meningiomas: Report of 6 cases with emphasis on atypical morphology and exploratory immunohistochemistry

AIMS

To investigate the histological and immunohistochemical features of primary ectopic meningiomas (PEMs), especially those of primary ectopic atypical meningiomas (PEAMs).

METHODS AND RESULTS

We examined 6 cases of PEM, including 2 PEAM cases, which occurred separately in left nasal cavity, left lower lung, right neck, left orbit, right upper lung, and left upper lung by histological and immunohistochemical analysis. In general, of the 6 PEM cases analyzed, 4 cases exhibited morphology of Grade Ⅰ, including 1 fibrous, 1 meningothelial, and 2 transitional variant. The remaining 2 cases shared similar atypical morphology of Grade Ⅱ. The tumors were distributed in sheet-like patterns with loss of architecture of classic meningiomas. Significant hypercellularity, multi-focal necrosis, and thin-walled blood vessels were identified. The mitotic figures were estimated at 6 per 10 high-power fields in one case, and 8 mitotic figures in another. Immunohistochemically, the 6 PEM cases were all positive for Vimentin and EMA, while none showed immunostaining for CKpan, S-100, CD34, STAT6, SMA, Syn or Bcl-2. 4 PEM cases of Grade Ⅰ were immunoreactive for PR but negative for P53, while the 2 PEAM cases displayed negative staining for PR but positivity for P53. As for Ki-67, the positive staining of 4 Grade Ⅰ cases was no greater than 2%, while the positive rates of the 2 PEAM cases were 10% and 20%.

CONCLUSIONS

Our study has expanded cases of PEMs, especially the 2 PEAM cases in rare sites. Our study has also further summarized the pathological features of PEMs, focusing on the histological features of PEAMs, and the immunohistochemical features worthy of further investigations.

Primary pulmonary meningioma: A case report and review of the literature

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.

CASE SUMMARY

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.

CONCLUSION

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.

Primary pulmonary meningioma presenting as multiple lung nodules: A case report

Primary pulmonary meningioma (PPM) is a very rare and mostly benign disease. Although PPM is incidentally detected as a solitary pulmonary nodule on X-ray or chest computed tomography, it does not have unique radiological characteristics; thus, it is difficult to differentiate it from other lung tumors. A healthy 54-year-old man visited our hospital because of multiple variable-sized lung nodules. He had no contributive medical history and no abnormality that was suggestive of extrapulmonary malignancy. Video-assisted thoracoscopic wedge resection was undertaken for diagnosis, and the tumor cells were histopathologically confirmed as PPM. Brain magnetic resonance imaging revealed no intracranial tumor. The patient has been well and without any progression of the remaining lesions over 24 months. Here, we present the clinicopathological features of this case in which the patient's nodules were mistaken for multiple metastatic lung nodules.

Radiological manifestations, histological features and surgical outcomes of pulmonary meningothelial proliferation: a case series and rethinking

Background

Lung cancer screening with computed tomography (CT) has been adopted worldwide. Consequently, there is an increase of some previously rarely reported lesions, like pleuropulmonary meningothelial proliferation (PMP), which included metastatic pulmonary meningiomas (MPMs), primary pulmonary meningiomas (PPMs) and minute pulmonary meningothelial-like nodules (MPMNs). To date, the understanding of the clinical management of PMP is limited.

Methods

We retrospectively searched PMP (MPMs, PPMs, and MPMNs) on the medical database (May 2005 to April 2019) of our department, and extracted the demographic and perioperative information. The last follow-up was in May 2019.

Results

A total of 78 patients, including 16 (20.5%) males and 62 (79.5%) females, were enrolled, with the median age as 61 (range, 27–78) years. There was 1 case with multiple MPMs, 4 cases with PPMs and 73 cases with MPMNs. On CT, MPMs manifested as round nodules with solid or part-solid components. PPM mainly presented as an isolated, round, solid, and well-circumscribed nodule, with or without lobulation. While MPMNs often showed as multiple, round, randomly-distributed, solid or partly-solid nodules, most of which were in tiny size. Histologically, MPM, PPM, and MPMN had similar morphological and immunohistochemical (IHC) features. As to the surgical outcomes, the case with multiple MPMs had undergone a progression after wedge resection and was in an active monitoring. And the four cases with PPMs and the five cases with MPMNs were all in regular surveillance.

Conclusions

PPM has variable radiological manifestations. But it can be histologically identified by the characteristic features. Although surgery is able to achieve satisfying prognosis, active observation is an alternative in selected cases due to the surgical invasiveness and the indolent nature of the disease.

Primary pulmonary meningioma: A rare case report of aspiration cytological features and immunohistochemical assessment

Ectopic meningioma is a generally rare type of benign tumor that very rarely occurs in the lung. Here, we report the cytological findings of a primary pulmonary meningioma with a particular focus on immunohistochemical (IHC) assessment. A healthy 60‐year‐old woman visited our hospital with an asymptomatic nodule in the right lower lung lobe. She had no particular past‐history and no other tumors in the central nervous system or elsewhere according to an imaging examination. Transbronchial fine‐needle aspiration cytology revealed clusters of spindle cells in a whorled formation and psammoma bodies. The tumor cells exhibited spindle‐shaped cytoplasm, small fusiform or round nuclei and numerous intranuclear cytoplasmic inclusions. IHC staining of the cytological specimen revealed that the tumor cells were positive for epithelial membrane antigen, negative for thyroid transcription factor‐1 and p40, and equivocal for claudin‐1. Progesterone receptor immunoreactivity of cytology specimen resulted negative at first by manual method but retrieved positive by an autostainer. Following segmentectomy, the pathological diagnosis was a meningothelial meningioma. The patient has remained well without recurrence for 36 months postoperatively. Because the cytological preparation exhibited characteristic findings of meningioma, a correct diagnosis based on pre‐operative cytological findings with appropriate IHC would be possible. Here, we report the cytological and IHC features of this case and highlight the importance of IHC‐quality assurance.