title: Multiple primary pulmonary meningiomas: 20-year follow-up findings for a first reported case confirming a benign biological nature.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Thoracic Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan. Electronic address: ysatoh@med.kitasato-u.ac.jp.
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Satoh
authors.affiliation: Department of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan. Electronic address: ishikawa@jfcr.or.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishikawa
keywords: Benign; Case report; Multiple; Primary pulmonary meningioma