MUC5B concentration in the BALF of NSCAP group was higher than that in SCAP group [NSCAP 13.56 μg/ml (IQR 5.92–25.79) vs. SCAP 8.20 μg/ml (IQR 4.97–14.03), p = 0.011]. Here, MUC5B is linked to syringocystadenoma papilliferum.