A 34-year-old woman with thrombotic thrombocytopaenic purpura and severe myasthaenia gravis developed progressive respiratory insufficiency. A chest CT was undertaken. CT showed a patchy distribution of areas with ground-glass opacification in both lungs, more pronounced in the central parts of both lungs (Fig. 9) . There was also a superimpo-sition of a linear pattern. Most of the lines were thickened interlobular septa. The diagnosis of pneumocystis jirovecii pneumonia was made based on clinical and laboratory findings.