Clinicopathologic features of minute pulmonary meningothelial-like nodules.

Purpose Minute pulmonary meningothelial-like nodules are incidentally discovered in lung specimens. We analyzed the clinicopathologic features of 14 cases identified in surgically resected lungs. Methods Among patients who underwent lung resection in our hospital from October 2007 to March 2016, 14 were found to have minute pulmonary meningothelial-like nodules. The clinical parameters, radiologic findings, and pathologic features of these patients were retrospectively reviewed using the medical records. Results The patients included 4 men and 10 women, with a mean age of 69 years (range 53-82 years). The coexisting main disease was adenocarcinoma in 8 patients, squamous cell carcinoma in 1, atypical adenomatous hyperplasia in 1, and metastatic pulmonary tumor in 3. In one patient, the minute pulmonary meningothelial-like nodules presented as multiple lung nodules on chest computed tomography. The median size of the nodules was 1.4 mm (range 0.3-6.0 mm). Similar to meningioma, one case had immunoreactivity to progesterone receptor and epithelial membrane antigen, although the minute pulmonary meningothelial-like nodules were not associated with a meningioma. Conclusions The relationship between minute pulmonary meningothelial-like nodules and meningioma should be investigated. If minute pulmonary meningothelial-like nodules are found on preoperative computed tomography, thoracoscopic lung biopsy is helpful for differential diagnosis.