hydroma

cystic hygroma (hygroma cys´ticum) an endothelium-lined, fluid-containing lesion of lymphatic origin, encountered most often in infants and children and occurring in various regions of the body, most commonly in the posterior triangle of the neck, behind the sternocleidomastoid muscle (hygroma colli cysticum).

Fleischmann's hygroma enlargement of a bursa in the floor of the mouth, to the outer side of the genioglossus muscle.