Lymphatic Malformations (Lymphangioma; Lymphangioma Circumscriptum; Cystic Hygroma; Cavernous Lymphangioma) By Denise M Aaron, MD, Dartmouth Geisel School of Medicine Reviewed / Revised Jan 2022 | Modified Sep 2022 View Patient Education Diagnosis Treatment Topic Resources Cystic Hygroma Lymphangioma Circumscriptum Lymphatic vascular malformations are elevated lesions composed of dilated lymphatic vessels.