Syringocystadenoma papilliferum behind the ear. The benign skin tumour is elevated, and ulcerated or crusty in the middle. It is virtually always located in the scalp or in the face. It most commonly grows in association with a sebaceous naevus and highly resembles a basal cell carcinoma. Malignant transformation is very rare but surgical excision of the lesion is, however, advisable.