Congenital dermal sinuses, dermoid and epidermoid cysts of the posterior fossa.

Dermal sinuses are abnormal communications between the skin and deeper tissues. Seven cases are presented of occipital dermal sinuses associated with dermoid or epidermoid cysts of the posterior fossa. The cysts were interdural, subdural and intracerebellar. Although they are benign lesions, there is a high incidence of complications, especially infections such as bacterial or aseptic meningitis and cerebellar abscess. The clinical features, radiological and tomographical characteristics, and the relationship to meningeal structures, dural sinuses and cerebellar parenchyma are described.