Clinicopathologic Characteristics and Surgical Treatment of Plurihormonal Pituitary Adenomas

Plurihormonal pituitary adenomas (PPAs) have recently been divided into 2 subtypes: pituitary specific transcription factor 1-positive plurihormonal pituitary adenomas (PIT-1+ PPAs) and plurihormonal adenomas with unusual immunohistochemical combinations (PAwUIC). The purpose of this study was to review patients with PPAs, elucidate their clinicopathologic characteristics, and present the surgical results.

Records were analyzed for 665 patients who underwent endoscopic endonasal transsphenoidal surgery for pituitary adenomas between 2007 and 2018. Data were reviewed for 27 patients who met the definition of PPAs and delineated regarding clinical, radiologic, pathologic features, and surgical outcomes.

Of the 27 patients, 18 had PAwUIC, and 9 patients were diagnosed with PIT-1+ PPAs. Twenty-four patients (88.8%) had macroadenomas, including 6 giant adenomas (≥4 cm) (22.2%). Cavernous sinus invasion was found in 12 patients (44.4%). Pathologic examinations showed high aggressivity in nearly half of the patients. Most patients with PAwUIC (77.8%) had features of nonfunctioning pituitary adenomas, and only 4 had features of hormone-secreting pituitary adenomas. Gross total resection rates were 57.1% for PAwUIC and 77.8% for PIT-1+ PPAs. The remission rate for hormone-secreting pituitary adenomas was 100% in this case series. Mean follow-up was 74.4 ± 33 months (range, 6-121 months) for overall groups.

To our knowledge, this is the first study to describe the clinicopathologic features of newly classified PPAs, which are characterized by aggressive behavior with higher values of percentage of cavernous sinus invasion. Relevant pathologic diagnosis of PPAs is crucial for appropriate management and follow-up.