RESUMEN
BACKGROUND: Double pituitary adenomas (DA) are two morphologically and immunohystochemically different tumours in the same gland. They are rare, generally small adenomas and divided in: separated, when clearly recognizable before or during surgery, and contiguous, when diagnosed only in the following histopathological examination. Acromegaly and Cushing's disease are the main prevalent clinical presentation. OBJECTIVE: We described two cases of DA in a surgical series over 16 years in a single center. METHODS: In September 2018, we diagnosed a DA in a man with acromegaly (case 1). In order to assess the presence of other cases of DA, we performed a retrospective analysis of the endonasal endoscopically operated sellar adenomas from January 2004 to December 2019. RESULTS: 468 pituitary adenomas were found. A DA with a Pit-1 positive macroadenoma (GH-TSH- PRL positive) and an ACTH microadenoma clinically silent in an acromegalic woman was retrospectively found (case 2). CONCLUSION: Our analysis confirms that DA are rare (0.4% of the pituitary adenomas) and often associated with acromegaly. Their pre-operatively diagnosis is difficult but clinician's awareness of DA can improve the diagnosis. The use of pituitary transcription factors could be useful in detecting DA.