Tumours with glomeruloid structures (Figure 5A) were particularly associated with a predominantly small cell morphology (10/19, 53% vs 88/261, 34%, p = 0.04, Fishers exact test), IDH1 mutation (7/8, 88% vs 139/262, 63%, p = 0.05, Fishers exact test) (Figure 5B), younger age at diagnosis (6/12, 50% vs 71/260, 27%, p = 0.06, Fishers exact test). This evidence concerns the gene IDH1 and neoplasm.