Non-adenomatosus lesions of the pituitary represent a small part of the intrasellar processes and they have heterogeneous presentation. Making a precise diagnosis is of great importance, as it may lead to more efficient management. A 65-year-old man was admitted to the hospital because of headache and right cranial nerve III palsy. Basic laboratory work-up was normal whereas endocrinological assessment revealed hypopituitarism without diabetes insipidus. Plain radiography showed an enlarged sella and frontal and paranasal sinusitis. Computed tomography (CT) and magnetic resonance imaging (MRI) of the sella revealed an intrasellar lesion with extension to the sphenoid and cavernous sinuses as well as the suprasellar region, exerting pressure on the optic chiasm. On T1-weighted images the mass had a low-intensity signal with a smooth enhancing rim with bright signal. Given the presence of multiple sinusitis and imaging characteristics a pre-operative diagnosis of pituitary abscess was made. The patient was operated via transphenoidal route and purulent material was drained out. Cultures of the material were positive for Staphylococcus aureus. Antibiotics as well as cortisol replacement therapy were given. Three months later hypopituitarism persisted but there was significant improvement in the neurological findings. We report a case of an unusual presentation of a pituitary abscess. High index of suspicion, the presence of associated conditions such as pituitary tumors, meningitis or sinusitis, as well as diabetes insipidus and specific imaging features are the main diagnostic clues. Pre-operative diagnosis, which will lead to prompt antibiotic therapy and transphenoidal drainage, can decrease high mortality and morbidity associated with this disease.