We have read with great interest the paper by Yuan et al. (1). Here, they present what we found to be the largest composite of cases of papillary pulmonary squamous cell carcinoma (PSCC) available to date. It is also the first population-based analysis of this sporadic type of pulmonary squamous cell carcinoma (SCC). Apart from some small and anecdotal reports, the literature about this entity is scarce. Since 1967, the World Health Organization (WHO)