There are many causes of macroglossia, including fatty infiltration. Unlike unique or multiple lipomas of the tongue, non-encapsulated adipocyte masses develop in the tongue in symmetrical benign lipomatosis. Only six cases have been reported in the literature.
Ghislain, P.-D., Garzitto, A., Legout, L., Alcaraz, I., Creusy, C., & Modiano, P. (1999). [Symmetrical benign lipomatosis of the tongue and Launois-Bensaude lipomatosis]. Annales de Dermatologie et de Venereologie, 126(2), 147-149. https://hdl.handle.net/2078.5/52635 (Original work published 1999)