Table 1. Characteristics of study population, 2004 to 2016.
| Characteristics | Thymic cyst (n=57) | Thymoma (n=43) | P |
|---|---|---|---|
| Demographic data | |||
| Age, years, mean (SD) | 54.7 (11.1) | 51.0 (12.6) | 0.115 |
| Sex, male, n (%) | 36 (63.2) | 24 (55.8) | 0.819 |
| Location, n (%) | 0.380 | ||
| Right | 18 (31.6) | 18 (41.9) | |
| Left | 27 (47.4) | 19 (44.2) | |
| Midline | 12 (21.0) | 6 (14.0) | |
| Size on CT scana, mm, mean (SD) | |||
| X | 21.7 (9.2) | 21.5 (5.8) | 0.861 |
| Y | 15.2 (5.7) | 15.5 (4.3) | 0.782 |
| Z | 25.7 (14.1) | 21.0 (6.2) | 0.018 |
| Contour, n (%) | <0.001 | ||
| Conformal to the shape of the adjacent mediastinum | 24 (42.1) | 2 (4.7) | |
| Smooth | 28 (49.1) | 14 (32.6) | |
| Lobulated | 5 (8.8) | 27 (62.8) | |
| Shape, n (%) | 0.519 | ||
| Ovoid | 25 (43.9) | 17 (39.5) | |
| Round | 24 (42.1) | 16 (37.2) | |
| Thymic shape | 8 (14.0) | 10 (23.3) | |
| Other CT findings | |||
| Calcification, yes, n (%) | 4 (7.0) | 0 (0.0) | 0.089 |
| Attenuation, high, n (%) | 28 (49.1) | 23 (53.5) | 0.401 |
| HU, median (1st and 3rd quartile) | |||
| Pre-contrast HU | 42.5 (27.5–57.0) | 45.5 (37.0–54.0) | 0.453 |
| Post-contrast HU | 38.0 (22.0–46.2) | 67.0 (47.0–85.0) | <0.001 |
| Enhancement (yes), n (%) | 10 (17.5) | 39 (90.7) | <0.001 |
| ∆HUb | −3.0 (−18.0, −5.0) | 24.0 (9.0–38.0) | <0.001 |
a, X is the longest diameter of the anterior mediastinal mass; Y is a diameter perpendicular to the longest diameter; Z axial diameter is a craniocaudal diameter of the mass. b, ∆HU is post-contrast HU minus pre-contrast HU. HU, Hounsfield unit.