There is a member of one of the post-Accutane groups on facebook who says she got “PAS” after using Retin-A or some other generic topical tretinoin product.
It’s worth considering that 38% of tretinoin was converted into isotretinoin (Accutane) by UV light in a study using cadaver skin and this percentage may be much higher in live skin due to active isomerase enzyme activity.
Lehman, Paul A., and Andrew M. Malany. “Evidence for Percutaneous Absorption of Isotretinoin from the Photo-Isomerization of Topical Tretinoin.” Journal of Investigative Dermatology , vol. 93, no. 5, Nov. 1989, pp. 595–99. ScienceDirect , https://doi.org/10.1111/1523-1747.ep12319721.
…A link to full text doesn’t appear to be available.