Diffuse pulmonary meningotheliomatosis: a rare cause of multiple pulmonary nodules

Abstract

This case describes a woman in her 50s who presented with recurrent lower respiratory tract infections. She was an ex-smoker and had worked on a livestock farm for many years. Chest radiograph and CT of the chest revealed multiple bilateral pulmonary nodules. Bronchoalveolar lavage and transbronchial biopsy did not confirm a unifying diagnosis and thus, surgical biopsy was pursued. Video-assisted thoracoscopic surgical guided biopsy of the right upper, middle and lower lobes demonstrated intraparenchymal minute nodules, consisting of bland epithelioid cells without any evidence of malignancy. The nodules stained positive for neural cell adhesion molecule (CD56) and progesterone receptor with weakly positive epithelial membrane antigen and smooth muscle actin. The combination of this characteristic staining pattern, the diffuse subcentimetre nature of the nodules and this clinical presentation fit with a diagnosis of the ultra-rare pulmonary disease, diffuse pulmonary meningotheliomatosis (DPM). This case highlights a rare cause of bilateral diffuse pulmonary nodules and thus, the breadth of differential diagnoses that need to be considered when approaching such a finding. Careful history-taking and thorough workup is often needed, typically requiring input from multiple specialties. DPM, while rare, should not be overlooked when considering the underlying cause of this presentation, especially in female patients. This case reiterates how common clinical presentations can unveil rare conditions and the contributions of physicians, pathologists and radiologists in the diagnosis and management of these complex diseases.