FIGURE 1.
Multi-phase contrast-enhanced CT of central PSP with higher Ki-67 index. Axial unenhanced CT image revealed a roundish isodense lesion in the left perihilar region with a CT density of 49 Hu (A). After administration of contrast medium, the lesion showed inhomogeneous enhancement with the enlarged left inferior pulmonary artery and overlying vessel sign (B). The lesions showed progressive and continuous enhancement in the arterial phase (75 Hu) (B), venous phase (96 Hu) (C), and delayed phase (110 Hu) (D). Immunohistochemical staining showed the Ki-67 reactive tumor cells accounted for about 10% (× 400) (E).
FIGURE 2.
Multi-phase contrast-enhanced CT of peripheral PSP with lower Ki-67 index. Axial unenhanced CT image revealed a peripheral isodense nodule in the right upper lobe with a CT density of 46 Hu (A). After administration of the contrast medium, the lesions showed homogeneous enhancement. The lesion showed progressive and continuous enhancement in the arterial phase (73 Hu) (B) and venous phase (102 Hu) (C), with a certain enhancement washout in the delayed phase (87 Hu) (D). Immunohistochemical staining showed the Ki-67 reactive tumor cells accounted for about 1% (× 400) (E).
TABLE 1.
Imaging and clinical comparisons between central and peripheral pulmonary sclerosing pneumocytomas (PSPs)
| Central PSPs (n = 15) | Peripheral PSPs (n = 18) | P | |
|---|---|---|---|
| Age (years) | 56.6 ± 8.5 | 51.6 ± 7.7 | 0.244 |
| Size (cm3) | 10.39 ± 3.25 | 4.65 ± 2.61 | 0.013* |
| Respiratory symptoms | |||
| n, present:absent | 11:4 | 4:14 | 0.037* |
| Unenhanced CT density (Hu) | 37.57 ± 15.61 | 43.64 ± 13.09 | 0.312 |
| Arterial phase CT density (Hu) | 67.09 ± 16.99 | 69.79 ± 18.67 | 0.767 |
| Venous phase CT density (Hu) | 91.36 ± 20.43 | 97.14 ± 21.38 | 0.373 |
| Delayed phase CT density (Hu) | 98.73 ± 26.53 | 74.71 ± 24.97 | 0.044* |
| Net enhancement value (Hu) | 61.47 ± 12.18 | 57.11 ± 10.28 | 0.205 |
| Peak enhancement value (Hu) | 98.73 ± 26.53 | 97.14 ± 21.38 | 0.828 |
| Enhancement washout value (Hu) | 3.8 ± 8.14 | 20.78 ± 10.22 | < 0.001* |
| TTP (s) | 100.81 ± 19.01 | 62.67 ± 20.96 | < 0.001* |
| Accelerated index | 0.63 ± 0.17 | 0.99 ± 0.25 | < 0.001* |
| Ki-67 index | |||
| n, low:high# | 9:6 | 17:1 | 0.030* |
| Overlying vessel sign | |||
| n, present:absent | 13:2 | 8:10 | 0.027* |
| Prominent pulmonary artery sign | |||
| n, present:absent | 11:4 | 5:13 | 0.015* |
| Obstructive inflammation/atelectasis | |||
| n, present:absent | 4:11 | 0:18 | 0.033* |
| Halo sign | |||
| n, present:absent | 1:14 | 7:11 | 0.046* |
| Peak phase | |||
| n, venous phase:delayed phase | 3:12 | 15:3 | < 0.001* |