Background: A pituitary abscess is a rare infectious disease in the sellar region, but potentially life-threatening, that can be easily misdiagnosed as a pituitary adenoma because pituitary abscesses and adenomas share many clinical manifestations, such as headaches, visual field changes, hypopituitarism, and imaging examinations suggesting a space-occupying lesion in the sellar region (Dalan and Leow, 2008). Case description: We report a unique case of a 26-year-old woman with headaches and blurred vision. Magnetic resonance imaging of the brain and pituitary demonstrated a high-signal ring around the pituitary and the optic nerve chiasma was squeezed upward by the lesion. Early misdiagnosis was pituitary adenoma apoplexy. During surgery, light yellow viscous liquid flowed from the dural incision. The intra-operative diagnosis was a pituitary abscess and drainage of pus. Post-operative anti-infective therapy, she was put on antibiotics and discharged after 1 weeks without sequelae. The patient was continued follow-up visits for 5 months without a recurrence. Conclusions: In retrospect, because of the rarity of pituitary abscess and the non-specific symptoms, it is difficult to make a diagnosis before surgery. A pituitary abscess can easily be misdiagnosed as a pituitary adenoma based on the similar clinical manifestations. Pituitary nuclear magnetic examination is the first choice for imaging and culture of the purulent drainage is the diagnostic gold standard. To thoroughly drain the pus, to wash operative region repeatedly with gentamicin saline that for avoiding the residual of the pus. And follow up so as to detect the suspicious pathogenetic condition in time. Adequate drainage and anti-infection are the preferred treatment (Kim et al., 2009).