Table 1 Comparison of clinical data between thymomatous MG patients and non-thymomatous MG patients

N

318

138

Age (years), mean ± SD

45.9 ± 16.3

50.0 ± 14.0

− 2.717

0.007

Sex (male/female)

168/150

66/72

0.965

0.326

Onset age of MG (< 50 years/ ≥ 50 years)

181/137

68/70

2.268

0.132

Preoperative course of MG (≤ 12 months/ > 12 months)

189/129

115/23

24.736

0.000

Dosage of pyridostigmine bromide(mg/d)

180 (0,540)

180 (0,600)

− 1.678

0.095

Osserman classification, n (%)

10.811

0.029

 I

74 (23.3%)

25 (18.1%)

 IIa

94 (29.6%)

32 (23.2%)

 IIb

132 (41.5%)

63 (45.7%)

 III

8 (2.5%)

11 (8.0%)

 IV

10 (3.1%)

7 (5.1%)

Surgical procedure (VATS/Sternotomy)

298/20

91/47

59.205

0.000

Surgical duration (min)

128.9 ± 41.6

129.1 ± 44.8

− 0.031

0.975

Perioperative myasthenic crisis, n(%)

32 (10.1%)

17 (12.3%)

0.511

0.475

WHO types of thymoma, n(%)

–

–

 A

–

0 (0%)

 AB

–

23 (16.7%)

 B1

–

32 (23.2%)

 B2

–

48 (34.8%)

 B3

–

10 (7.2%)

Mixed B type

–

24 (17.4%)

Micronodular thymoma with lymphoid stroma (MNT)

–

1 (0.7%)

Masaoka-Koga stage, n(%)

 I

–

31 (22.4%)

 II

–

76 (55.1%)

 III

–

27 (19.6%)

 IV

–

4 (2.9%)