Pietro Aretino's memoirs fake?

I have a Finnish paperback, published in 1974, that's said to have been written by Pietro Aretino, the famous satiricist and poet of the 16th century. The book is called Profane Memoirs or some such (Uskallettuja muistelmia in Finnish). No original title is given (or, actually, it's said on the back of the title page that no original title is known). The back cover copy claims that the text of the book was found in Venice after some floods and has never before been printed.

The catalogue of Sweden's Kungliga biblioteket says that the book Skamlösa memoarer was translated from "untitled Italian manuscript". The Swedish book was published in 1968.

Now, this seems like a hoax. The text however is full of stuff that no ordinary porn hack would know, for example an elaborate analysis of Michelangelo's work. And the fight and the duel scenes are quite well-written. This clearly isn't work of a Finnish or a Swedish writer.

I just can't find this book anywhere on-line. No site on Aretino says there's a book of Aretino's memoirs (and certainly not one that was found in Venice after the floods). Only books of Aretino's I find contain his poems, dialogues or plays - no prose.

If this were a hoax and published by some porn imprint, like, say, Olympia Press, you'd think it could be easily found on-line.

I find on Abebooks there's a book by "Aretino, Jr.", called Roman Hookers, Happy Hookers (Curtis 1973), but since that's later than the Swedish Skamlösa memoarer I don't think that has anything to do with the book here.

Can anyone shed any light on this? Is there a book that's claimed to be by Aretino containing his memoirs?