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 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 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.

SAT-265 An Asynchronous Double Growth Hormone Secreting Pituitary Adenoma as a Cause of Rapid Tumor Regrowth After Initially Successful Surgery

Background. Double pituitary adenomas are a rare entity, which requires clinical attention and a careful follow-up. Case report. A 37-year-old man presented with left-sided painful gynecomastia. He denied typical symptoms of excessive growth hormone (GH) secretion and did not show any acromegalic features. Due to low testosterone and LH levels with mild hyperprolactinaemia, the patient was referred to pituitary MR, which revealed an 11x13 mm right-sided sellar tumor. An increased IGF-1 was noted subsequently (1482 ng/mL; N 109-284 ng/mL), together with the lack of GH suppression in OGTT. Transphenoidal resection of pituitary tumor performed in 2012 led to biochemical (IGF-1 260 ng/mL, GH 0.08 ng/mL) and radiological remission of the disease. A histopathology report revealed a densely granulated somatotropic pituitary adenoma with mild nuclear atypia, expressing somatostatin receptors [sstr2A (+), sstr5 (+/-)]. Due to gradually increasing IGF-1 levels (with low, although rising, GH values ranging from 0.07 to 0.92 ng/mL) in subsequent years, OGTT was repeated in 2015, showing appropriate GH suppression. In 2016, however, acromegaly recurrence was confirmed both biochemically (increasingly high IGF-1 - 664 ng/mL - and unsuppressed post-OGTT growth hormone) and in MR imaging. The patient was reoperated in June 2017. The second histopathology reported an oncocytic somatotropic acidophil stem cell pituitary adenoma with Ki-67 >3% and mitotic figures. Subsequent anterior pituitary lobe insufficiency (adrenal, thyroid and gonadal axis) was found and adequately treated. Complete tumor removal was confirmed by MR performed three months after repeated surgery, as well as a low GH level (0.97 ng/mL), although accompanied by borderline IGF-1 values (277 ng/mL). Eighteen months after surgery, the recurrence of acromegaly was again confirmed, with adenoma regrowth and increased GH (2.31 ng/mL) and IGF-1 (474 ng/mL) levels. Octreotide LAR was started (despite retina wrinkling which was observed when lanreotide was administered before the first surgery), which led to a normalization of GH (0.96 ng/mL) and IGF-1 levels (152 ng/mL), as well as partial pituitary tumor regression after six months therapy. Conclusion. In a case of GH-secreting pituitary adenoma recurrence after apparent successful surgery, a double pituitary tumor with more aggressive histology should be considered.

Double pituitary adenomas in a large surgical series

Purpose To explore the incidence of double pituitary adenomas in a tertiary center for pituitary surgery and asses their clinical, imaging and histopathological features. Methods The medical records of the patients operated on for pituitary tumors at the Department of Neurosurgery of Military Institute of Medicine in Warsaw, Poland between the years 2003 and 2018 were retrospectively analyzed. Among the 3270 treated patients, the diagnosis of double pituitary adenoma was established in 22 patients. Clinical, laboratory, detailed histopathological and diagnostics imaging data were collected and analyzed. Results There were 21 cases of synchronous and one case of asynchronous double pituitary adenoma. The main clinical finding was acromegaly (12/22) followed by Cushing’s disease (3/22). The diagnosis of synchronous double pituitary adenoma was suspected in the preoperative MRI in 11 patients. In the remaining patients the diagnosis of contiguous double pituitary adenoma was confirmed in the histopathological examination. There was no predilection for gender and the mean observation time was 74.2 months. In one case of Cushing’s disease the occurrence of double pituitary adenoma led to the initial failure of achieving hormonal remission. One patient presented with double pituitary adenomas as a manifestation of Carney complex. Conclusions Double pituitary adenoma is a rare entity that can pose a significant challenge especially in the setting of Cushing’s disease. Careful inspection of preoperative MRI and diagnostic work-up before transsphenoidal surgery and thorough histopathological microscopic examinations with immunohistochemical staining for all pituitary hormones is essential for establishing the diagnosis of double pituitary adenoma.