Sprouting epidermoid cysts

Five unusually shaped (i.e. ‘sprouting’) epidermoid cysts in the upper lip, elbow and foot are reported. The tumours seldom produced symptoms. The maximum diameter was 25–48 mm. The complete removal including a sprouting bud is necessary. Histologically, partial to complete cyst wall rupture was recognised. A pulsion diverticulum due to variations in the thickness and strength of the cyst wall, a foreign body reaction against inner keratinous mass without obvious bacterial infection, and/or outer fibrous band(s) acting as constriction band(s), are proposed as possible causes of the ‘sprouting’.