Multiple primary pulmonary meningiomas: 20-year follow-up findings for a first reported case confirming a benign biological nature

INTRODUCTION: Primary pulmonary meningiomas (PPMs) are very rare neoplasms, and we reported the first multiple case of PPMs in 1998. Usually, PPMs are slow-growing tumors with a good prognosis. Herein, we reported a rare multiple case of PPMs with an extremely long clinical course. PRESENTATION OF THE CASE: An 84-year-old Japanese woman with a history of multiple PPMs histologically confirmed as having a right-sided slowly growing lung nodule for 20 years. In 2010, we also reported the additional clinical course in the initial case 10 years after surgery implying a benign biological nature. Subsequent to that report, new lesions appeared in the bilateral lung fields with quite a slow growth rate. She was asymptomatic, and no tumor was observed in the cranial cavity during the course of her disease. DISCUSSION AND CONCLUSION: This case illustrates rare multiple PPMs and highlights their biological behavior with very slow progression from a most likely benign tumor over a 20-year period.