Prominent Diffuse Ground-Glass Opacities: A Challenging Case of CTD-ILD, IPH, and Secondary PAP Coexistence

Background: Diffuse ground-glass opacities (GGOs) are a commonly observed radiographic finding in pulmonary imaging, frequently associated with various pulmonary pathologies. The etiology of ground-glass opacities is multifactorial, with connective tissue disease-associated interstitial lung disease (CTD-ILD), pulmonary haemosiderosis (PH), and pulmonary alveolar proteinosis (PAP) being potential underlying causes. Since the radiographic presentations of PH and PAP may overlap with those of CTD-ILD, a comprehensive differential diagnosis is crucial. Case presentation: This paper presents the case of a 24-year-old female patient who initially presented with thrombocytopenia and pulmonary opacities, accompanied by exertional dyspnoea, and was diagnosed with CTD-ILD. After treatment with glucocorticoids and mycophenolic acid (MPA), her symptoms improved. However, chest imaging over 8 months revealed recurrent fluctuations in pulmonary ground-glass opacities. Nine months after treatment, fibreoptic bronchoscopy revealed greyish-white gelatinous material in the bronchoalveolar lavage fluid. Anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies were found to be <1 IU/ml, leading to the diagnosis of CTD-ILD with SPAP. Atorvastatin was then added to the treatment regimen. Despite ten months of statin therapy, Chest CT findings show that the condition remains recurrent. After 12 months of statin therapy, re-examination of the lung biopsy specimen revealed alveolar hemosiderin deposition, confirming the diagnosis of CTD-ILD with idiopathic pulmonary hemosiderosis (IPH). Conclusion: This case report describes the rare occurrence of SPAP in a patient with CTD-ILD complicated by IPH. This case highlights the importance of vigilance for IPH and SPAP in patients with CTD who present with persistent or fluctuating pulmonary imaging abnormalities that do not adequately respond to conventional therapy. Prompt alveolar lavage and lung biopsy are essential for establishing a definitive diagnosis.