Intra-Articular Synovial Sarcomas: Incidence and Differentiating Features from Localized Pigmented Villonodular Synovitis

Table 1

Data on all synovial sarcomas from the SSG Central Register.

	Mean (SD)
Age (years)	38.8 (19.2)
Size (cm)	7.3 (4.9)
Male : female ratio	1 : 1
Metastasis at primary diagnosis	8.3%
Disease-free survival at latest follow-up	54%
Disease-free survival versus age
≤20 years of age (68/83)	82%
>20 years of age (157/331)	47%
Disease-free survival versus tumor size
≤5 cm (131/175)	75%
>5 cm (95/240)	40%
Disease-free survival versus age and tumor size
≤20 years of age and ≤5 cm (40/41)	98%
>20 years of age and >5 cm (58/179)	32%
Patients with metastasis at primary diagnosis	Mean (SD)
Size (cm)	10.6 (4.8)

32 cases had missing data regarding age. 31 cases had missing data regarding tumor size.