Table 1.

Clinical characteristics and morphological MRI features of patients

	Primary cohort (n = 140)				Validation cohort (n = 69)
	IP (n = 90)	MT-IP (n = 50)	p		IP (n = 45)	MT-IP (n = 24)	p
Sex			0.906				0.789
Male	68 (75.8%)	39 (78.8%)			29 (63.8%)	17 (70.8%)
Female	22 (24.2%)	11 (21.2%)			16 (36.2%)	7 (29.2%)
Age (years)	56 ± 12	58 ± 12	0.289		56 ± 14	59 ± 12	0.334
Maximum diameter (mm)	47.7 ± 13.6	62.9 ± 13.7	<0.001		48.1 ± 14.7	67.4 ± 19.5	<0.001
Bony erosion			<0.001				<0.001
Yes	8 (8.9%)	25 (50.0%)			6 (13.3%)	13 (54.2%)
No	82 (91.1%)	25 (50.0%)			39 (86.7%)	11 (45.8%)
Orbit or intracranial invasion			<0.001				<0.001
Yes	5 (5.6%)	18 (36.0%)			2 (4.4%)	9 (37.5%)
No	85 (94.4%)	32 (64.0%)			43 (95.6%)	15 (62.5%)
Loss of convoluted cerebriform pattern			<0.001				<0.001
Yes	19 (21.1%)	38 (76.0%)			8 (17.8%)	19 (79.2%)
No	71 (78.9%)	12 (24.0%)			37 (82.2%)	5 (20.8%)

CCP, convoluted cerebriform pattern; IP, inverted papilloma; MT-IP, inverted papilloma with malignant transformation

Data are presented as n (%) or mean ± standard deviation.