These cells, which are a component of the innate immune system, are observed in several types of NF1-related tumours, including cNFs.25,76 Mast cells are thought to serve a complex pro-tumour role in these diseases.77 The presence of mast cells in cNFs was first described by Greggio in 1911, and it was later hypothesised that they may be an important element of the cNF microenvironment.25,78 Other studies have clarified the role of mast cells in cNF growth. The gene discussed is NF1; the disease is neoplasm.