Cytology of primary pulmonary meningioma. Report of the first multiple case.

BACKGROUND: Ectopic meningiomas arising in the lung are rare. We report here the first multiple primary case diagnosed by intraoperative imprint cytology.

CASE: Asymptomatic pulmonary nodules, two in the left and three in the right lung, were found in a 61-year-old woman, and video-assisted thoracoscopic surgery was undertaken. Because the largest tumor was diagnosed as a meningioma by intraoperative imprint cytology using an excised biopsy specimen, further resection was not performed immediately. Histopathologically the tumor was characterized by whorled nests of cells accompanied by psammoma bodies intermingled with a fibrous pattern. The diagnosis was a transitional meningioma, positive for vimentin and epithelial membrane antigen and negative for keratin immunohistochemically. All the nodules were subsequently surgically resected and showed a similar cytohistologic appearance. Ultrastructurally the tumor cells demonstrated interdigitation of adjacent plasma membranes with numerous desmosomes and hemidesmosomes, typical of meningiomas. We failed to detect another primary tumor in the nervous system, and at this writing the patient was healthy three years after the operation.

CONCLUSION: Because of the characteristic cytomorphologic features of primary pulmonary meningioma, the cytologic approach provides useful information for therapy.