Pituitary abscess (PA) is an infrequent disease, which consists of an infection within the sella turcica that might be life-threatening. We present here two cases of this rare entity. Case 1: A 53-year-old woman was followed for an incidentally found pituitary cyst. Six years later the cyst enlarged and transsphenoidal surgery was performed. Two years later, the patient developed sudden onset of intense headache and nausea. The MRI showed a 2 by 2.5 cm sellar and suprasellar mass, that enhanced peripherally with gadolinium contrast and became hyperintense in T2-weighted images, suggesting a new-onset cystic lesion. During transsphenoidal surgery, large amounts of purulent material were drained from the sella. The cultures were positive for Klebsiella Ozaenae. Case 2: A 63-year-old woman, 4 years after transsphenoidal resection of a GH-secreting macroadenoma, developed a new sellar 2.6 cm cystic mass. On re-operation, purulent material was drained from the sella. The lesion persisted on the MRI and visual acuity worsened so a repeat pituitary decompression was carried out 6 months later, obtaining the same pathological results. Three years later, the MRI still shows the same mass. She feels well and her physical examination and clinical history are unremarkable. These cases illustrate the difficulties in the diagnosis and management of this rare entity.