Diencephalic syndrome (DS) is a rare condition characterized by profound emaciation and failure to thrive (with normal caloric intake and normal linear growth), hyperalertness, hyperkinesia and euphoria, in the presence of hypothalamic tumors.

Nontender, round and firm, but slightly compressible, intradermal or subcutaneous cyst measuring 0.5-5 cm in diameter. Epidermal cysts are intradermal or subcutaneous tumors, grow slowly and occur on the face, neck, back and scrotum. They usually appear at or around puberty, and as a rule an affected individual has one solitary or a few cysts.