Imaging and molecular investigations. (A) Serial computed tomography chest images (2007-2015). (i) June 2007: no respiratory symptoms. Normal imaging. (ii) January 2015: no respiratory symptoms but evidence of progressive MPN/MDS. Early interstitial changes are present. (iii) June 2015: cough and breathlessness. Progressive interstitial changes plus air space shadowing are present. (iv) September 2015: respiratory failure secondary to PAP. “Crazy paving” changes plus consolidation characteristic of PAP visible. (B) Comparison of somatically acquired c.1168_1170delAAG p.390delK GATA2 mutations. Three patients have been reported with somatically acquired p.390delK mutation in GATA2. Germ line mutations in GATA2 and other cooperating mutations in ASXL1 or RUNX1 were also present in two previous cases. Fib, fibroblast; LCL, lymphoid cell line; LN, lymph node; NT, not tested; PB, peripheral blood.