We report a case of anterior hypopituitarism showing recurrent pituitary mass associated with central diabetes insipidus. A 76-year old woman was hospitalized with general fatigue and 5 kg body weight loss. Endocrinological examinations and pituitary provocative tests demonstrated hypopituitarism and central diabetes insipidus. T1-weighted image of magnetic resonance imaging (MRI) revealed an intrasellar cystic mass with ring enhancement suggesting pituitary abscess. MRI films subsequently obtained from another hospital and studied retrospectively showed intrasellar cystic mass with ring enhancement 4 years earlier, and a mass shape that was decreased after 2 years. Over the subsequent years, the patient has remained asymptomatic with hormone replacement therapy only. Cystic pituitary adenoma or Rathke's cleft cyst with repeated infection may be involved in the repeated change of pituitary mass shape although neither pituitary surgery nor a pituitary biopsy was performed because of the patient's age and condition. It is reported that apparent recurrence of Rathke's cleft cysts after initially successful surgery was higher than suggested by previous reports, and that long-term follow-up with pituitary imaging and neuroophthalmological assessment is essential. Careful evaluation by follow-up brain MRI is needed in the present case to prevent future recurrence of pituitary abscess.