RESUMO
Primary CNS lymphomas (PCNSLs) constitute 3% of all intracranial neoplasms. From these, primary pituitary lymphomas (PPLs) represent extremely rare clinical entity. Nearly all of PCNSLs are non-Hodgkin diffuse large B-cell lymphomas. We present a 60-year-old female with right-sided third cranial nerve palsy, mild bitemporal visual field deficit, severe cephalea, and polyuria-polydipsia. Hypopituitarism with hyperprolactinemia was confirmed; brain imaging revealed a 16 mm-diameter sellar mass with suprasellar extension. A presumptive diagnosis of pituitary adenoma was established. The patient underwent a neurosurgical intervention. Histopathological examination and immunophenotyping (cytokeratin, CD45+, CD79+, bcl-2-) verified high-grade B-cell non-Hodgkin lymphoma of the Burkitt type. Systemic work-up showed no other foci of lymphoma, the patient's HIV status was negative, Epstein-Barr virus status was not disclosed. Although PPL can be undistinguishable from pituitary adenoma at imaging, one should consider lymphoma when evaluating an invasive sellar mass that is iso- to hypointense on T2-weighted magnetic resonance images, particularly when the patient is immunocompromised or old and presents with diabetes insipidus, cranial nerve palsy and fever of unknown origin in addition to the expected finding of hypopituitarism.