False positive fistula test is associated with -
False Positive Fistula Test–Hennebert Sign

Fistula test is positive without the presence of fistula.
It is seen in case of congenital syphilis and Meniere’s disease
In congenital syphilis, stapes foot plate is hypermobile while in meniere’s disease there is a fibrous band connecting utricular macula to the stapes footplate.
In both these conditions, movements of stapes result in stimulation of utricular macula which will cause nystagmus and vertigo leading to false positive fistula test. This is called as Hennebert sign.

Ref. Dhingra 5/e, p 47
Perilymph fistula
Malignant sclerosis
Congenital syphilis
Cholesteatoma