1) The vinegar test is so bad that most STD experts never use it. It is especially unreliable, with both false negative (missing HPV infections) and false positive results (abnormal in the absence of HPV) on dry skin. So the negative result may be a little reassuring, but only slightly.
2) Warts would maintain size and shape, no spreading with the skin.
3) No.
4) Warts tend to form where sexual friction is greatest, so it is logical they would be a little more frequent on prominent surfaces. But this probably isn't important for lesions on the thigh.
Bottom line: I'm pretty sure these aren't warts.
Good luck-- HHH, MD
about a year ago I noticed a white line on my penis just under the head, it was 1mm thick x 1.5 cm long. The doctor back then said it was a whart and gave me some treatment which got rid of it. A year down the track it came back, 1mm thick x 1.5cm long but this time just a bit more up and to the right. I went to two doctors and one said it was not a wart because of the shape and another one said that it was! I am wondering if warts can be thin and straight and if it's not than what is it.