Lymphangioma circumscriptum: an example of Whimster's hypothesis

Lymphangioma circumscriptum is an uncommon hamartomatous malformation that is not only localized to an area of skin, but also spreads to subcutaneous tissue and muscle (Whimster's hypothesis). We describe a 7-year-old boy with a bluish plaque on the left side of the back and abdomen with clusters of translucent vesicles (frog spawn). Magnetic resonance imaging showed the lymphangioma had spread to muscles and even fat adjacent to the left kidney. We decided against radical surgery as it would have been too aggressive, and limited excision can produce new surface lymphangiomas.