The many faces of diffuse cystic lung disease: Clinicoradiological and pathological correlation in a case series

Diffuse cystic lung disease (DCLD) comprises a heterogeneous group of disorders characterized by multiple pulmonary cysts on high-resolution computed tomography (HRCT). Because of overlapping clinical and radiological features, establishing the underlying etiology remains challenging and requires integrating imaging and histopathology with multidisciplinary discussion (MDD). We describe five patients with DCLD evaluated at a tertiary care centre. The final diagnoses included two cases of lymphocytic interstitial pneumonia (LIP), one associated with primary Sjögren’s syndrome and one probable idiopathic LIP, two cases of Lymphangioleiomyomatosis (LAM), and one case of pulmonary Langerhans cell histiocytosis (PLCH). Clinical presentations ranged from chronic dyspnea and cough to recurrent pneumothorax and pleural effusion. HRCT demonstrated characteristic yet overlapping cystic patterns that guided the differential diagnosis. Transbronchial lung cryobiopsy (TBLC) was successfully performed in all patients and together with immunohistochemistry, it established the histopathological diagnosis. Integration of clinical, radiological, pathological, serological and immunohistochemical findings through MDD enabled accurate diagnosis and appropriate management. DCLD encompasses a broad spectrum of disorders with diverse etiologies and overlapping imaging appearances. A systematic multidisciplinary approach incorporating HRCT pattern recognition, TBLC, histopathology, immunohistochemistry and clinical correlation is essential for establishing an accurate diagnosis and guiding disease-specific management. Our experience highlights the diagnostic utility and safety of TBLC in evaluating diffuse cystic lung diseases.