Teaching Case

A 48-year-old woman with systemic lupus erythematosus (SLE), complicated by interstitial lung disease since 2006 and desquamative interstitial pneumonia diagnosed in 2017, was treated with cyclophosphamide for severe disease progression, undergoing high-resolution CT control scans forward to 2024.

High-resolution CT (HRCT) scans from 2007 to 2011 show slight changes with ground-glass opacifications (GGO) and small cysts developed during this period (Figure 1).

HRCT scans in 2016 and 2017 show alternating lung changes with added pneumonitis, interlobar septal thickening, and pleural accumulation on the left side. The last picture has persistent GGO and localised slight fibrosis (Figure 2).

HRCT from 2018 to 2023 show increasing localized fibrosis with cyst development, sometimes added interstitial infectious changes, cyst wall thickening, and bronchiectasis (Figure 3).

HRCT scans from 2023 and 2024 show a tendency towards repeated infections and further development of cysts with alternating wall thickening. The last scan with the infection at rest, shows established parenchymatous cysts. Volume measurement revealed the beginning shrinkage of the parenchyma (Figure 4).

Systemic lupus erythematosus (SLE) is an autoimmune disease known for its multiorgan involvement, including the lungs, joints (arthritis), skin (photosensitive rashes), kidneys (glomerulonephritis), and blood (cytopenia). It is predominantly affecting women, with hormonal influences contributing to its onset [1].

Pulmonary involvement occurs in up to 50% of patients, including pleuritis, pleural effusion, pneumonitis, diffuse alveolar haemorrhage, vasculitis, pulmonary hypertension, and rarely cavitary lesions [2]. The infrequent occurrence of lung cavitations in SLE contributes to a limited understanding of their pathogenesis, though they are often linked to infectious aetiologies, vasculitis, or necrotic infarctions [3].

Desquamative interstitial pneumonia is a rare interstitial lung disease (ILD). It is characterised by the accumulation of alveolar macrophages and emphysema, with minimal fibrosis or neutrophilic inflammation [4]. ILD is a rare manifestation of SLE and typically presents as nonspecific interstitial pneumonia.

Pulmonary involvement in SLE is associated with a high expression of type I interferon (IFN)-regulated genes, termed “IFN signature”, which promotes autoantibody synthesis and disrupts immune tolerance in the lungs [5]. While pulmonary involvement in SLE is frequent, pulmonary symptoms manifest in only 4%–5%. These can vary from an asymptomatic to persistent exertional dyspnoea, pleuritic chest pain, nonproductive cough, and decreased exercise tolerance.

Diagnosis of interstitial lung disease relies on clinical, radiological, and pathological data. A high-resolution-computed tomography (HRCT) reveals abnormalities such as thickened interlobular septa, bronchiectasis, and bronchial wall thickening [1]. Pulmonary function tests typically show a restrictive pattern with decreased forced vital capacity and diffusing capacity for carbon monoxide. Surgical lung biopsy remains the most sensitive method for obtaining an accurate pathological diagnosis [5,6]. Desquamative interstitial pneumonia may manifest with ground glass opacities on HRCT, resembling nonspecific interstitial pneumonia, making the finding nonspecific. Therefore, biopsy consideration is crucial [7].

Management of pulmonary complications in active SLE involves systemic corticosteroids as a primary treatment, often combined with cyclophosphamide or mycophenolate mofetil, followed by either rituximab or intravenous immunoglobulins. Despite limited evidence, systemic corticosteroids can improve some patients' inspiratory vital capacity and diffusing capacity for carbon monoxide [4,8].

In our case, the endpoint of lung changes is the cysts and bronchiectasis in both lung areas, irreversible changes with a high impact on lung function, and a high risk for intercurrent infection, spontaneous pneumothorax, pulmonary hypertension, and lung shrinking syndrome.

Written informed patient consent for publication has been obtained.