Minute pulmonary meningothelial-like nodules in the transbronchial biopsy of a lung transplant recipient

Minute pulmonary meningothelial-like nodules (MPMN) are small (100 µm–few mm) asymptomatic nodules, often identified as incidental findings in microscopic studies of lung samples. MPMNs have been found in subjects ranging in age from 12 to 91 years (up to 85% women) and more frequently in the right lung. The lesions consist of whorls/nests of moderately sized cells with eosinophilic cytoplasms. The cells are spindle or elongated. The nuclei are oval with finely granulated chromatin and small or absent nucleoli. These lesions have been initially called “minute pulmonary tumors representing chemodectomas.”