We present a 13-year-old patient with pituitary abscess, who suffered from vertigo, headache and left temporal hemianopsia. Intrasellar or suprasellar lesion was suspected clinically. The CT and MRI showed an intrasellar mass with left suprasellar extension, and marked peripheral wall enhancement was identified. A pituitary abscess or abscess formation in a pituitary tumor was impressed preoperatively. Primary pituitary abscess formation was confirmed by the trans-sphenoidal surgery. Enhanced CT and MRI could contribute to the pre-operative diagnosis.