Two Cases of Double Adenomas in a Surgical Series over 16 Years in a Single Centre.

Background Double pituitary adenomas (DA) are two morphologically and immunohystochemically different tumors 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. Method 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 small 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.