Central and peripheral pulmonary sclerosing pneumocytomas: multi-phase CT study and comparison with Ki-67

Abstract

Background. This study aimed to evaluate the multi-phase CT findings of central and peripheral pulmonary sclerosing pneumocytomas (PSPs) and compared them with Ki-67 to reveal their neoplastic nature.
Patients and methods. Multi-phase CT and clinical data of 33 PSPs (15 central PSPs and 18 peripheral PSPs) were retrospectively analyzed and compared their multi-phase CT features and Ki-67 levels.
Results. For quantitative indicators, central PSPs were larger than peripheral PSPs (10.39±3.25 cm3 vs 4.65±2.61 cm3, P=0.013), and tumor size was negatively correlated with acceleration index (r=-0.845, P<0.001). The peak enhancement of central PSPs appeared in the delayed phase, with a longer time to peak enhancement (TTP, 100.81±19.01 s), lower acceleration index (0.63±0.17), progressive enhancement, and higher Ki-67 level. The peak enhancement of peripheral PSPs appeared in the venous phase, with the shorter TTP (62.67±20.96 s, P<0.001), higher acceleration index (0.99±0.25, P<0.001), enhancement washout, and lower Ki-67 level. For qualitative indicators, the overlying vessel sign (86.67%vs44.44%, P=0.027), prominent pulmonary artery sign (73.33%vs27.78%, P=0.015), and obstructive inflammation/atelectasis (26.67%vs0, P=0.033) were more common in central PSPs, while peripheral PSPs were more common with halo sign (38.89%vs6.67%, P=0.046).
Conclusion. The location of PSP is a possible contributing factor to its diverse imaging-pathological findings. The tumor size, multi-phase enhancement, qualitative signs, and Ki-67 were different between central and peripheral PSPs. Combined tumor size, multi-phase findings, and Ki-67 level are helpful to reveal the nature of the borderline tumor.
Key words: pulmonary sclerosing pneumocytoma; location; multi-phase computed tomography; Ki-67