To study the clinicopathological characteristics, immunophenotype, pathologic diagnosis and differential diagnosis of diffuse pulmonary meningotheliomatosis (DPM).

The clinical data, histological features and immunohistochemical results of three cases of DPM collected from January 2016 to May 2018 at Guangdong Provincial People′s Hospital were analyzed, and the relevant literature reviewed.

The three DPM patients age was 53, 69 and 74 years. The lesions consisted of multiple minute pulmonary meningothelial-like nodules profusely involving the lungs. Microscopically, they showed typical morphology, characterized by medium-sized elongated tumor cells resembling meningothelial cells with whorled/nested clusters. The cells were uniform and had abundant eosinophilic cytoplasm with oval nuclei with delicate chromatin. Immunohistochemical staining showed tumor cells were diffusely and strongly positive for EMA, vimentin and PR, but were negative for CAM5.2, CgA, Syn, CK7 and TTF1.

DPM is extremely rare, and may be confused with primary interstitial pulmonary processes and metastatic malignant tumors of lung. Recognition of this entity is essential for pathologists to avoid misdiagnosis and unnecessary treatment.

Lung diseases; Multiple pulmonary nodules; Diagnosis, differential; Immunohistochemistry; Diffuse pulmonary meningotheliomatosis