I'm afraid I can't be much help, just wanted to offer my thoughts and prayers for your daughter. I was unaware that a person could have both venous and lymphatic malformations, but then again I am new to this world too. My only suggestion is to get many opinions--write to the experts on this site, they are such an amazing resource! We made the unfortunate mistake of not questioning our doctor or his diagnosis of my 18 month old son--but I am learning that these malformations are very commonly misdiagnosed. Our dr. knew nothing about LMs and performed surgery on what he thought was a cleft cyst. Luckily he is an amazing surgeon and my son looks awesome, but he still wasn't the best person to see my son in the first place. Live and learn!
It was only after surgery that he was again misdiagnosed with arteriovenous malformation in his neck, but I knew we needed a second opinion, as I was convinced it was lymphatic malformation instead. So I did more research to find a doctor who specialized in LMs and he confirmed my suspicions--he has macrocystic LM. As moms we have that gut instinct that we can't ignore! Good luck, and if you don't feel confident in your doctors keep searching!