We present a case of a 20-year-old woman reporting polyarthritis, muscle weakness, dyspnoea and multiple intensive care unit admissions due to respiratory failure, without haemoptysis, since 4 months of age. The mother had systemic erythematous lupus. On physical examination, digital clubbing and mild desaturation were found. Laboratory tests demonstrated 1:640 nuclear homogeneous pattern antinuclear antibodies (ANA) and erythrocyte sedimentation rate (ESR) of 61 mm. Spirometry exhibited forced vital capacity of 53%.

High-resolution CT (HRCT) showed cysts and ground glass with reticular infiltrates (figure 1A-D). In 2006, she underwent a pulmonary biopsy, which revealed follicular bronchiolitis (figure 2A-D), without features of haemorrhage on biopsy such as haemosiderin laden macrophages.

HRCT appearances. (A, B) Multiple well-circumscribed cysts in the parenchyma (arrows) and parenchymal reticulation with architectural distortion (arrowheads); (C, D) scattered ground glass opacities, more extensive in the lower lobes (circles). These findings correspond to an interstitial lung disease of unclassifiable pattern with parenchymal cysts. HRCT, high-resolution CT.

Lung biopsy revealing. (A) Pulmonary parenchyma with lymphoid aggregates; (B) peribronchiolar (arrowhead) lymphoid aggregate with prominent germinative centre (arrow); (C) proliferation …