Central giant cell granuloma (CGCG) with polyostotic fibrous dysplasia (PFD) are rare lesions of the jaws and it is even less common for them to occur simultaneously, giving rise to hybrid lesions. When this type of mixed lesions are extensive, therapeutic alternatives are limited and extensive bone resections must often be performed. The aim of this case report is to document the remission of an extensive hybrid lesion (PFD + GCCG) of the mandible unexpectedly after the use of decompression therapy prior to knowing the result of the histopathological study; providing a successful result that can avoid resective surgeries in this specific type of infrequent mixed lesions.