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Abstract

While double pituitary adenomas have been found in approximately 1% of autopsy pituitaries, those in surgically resected material have been only rarely reported. We report herein 6 cases of double pituitary adenomas, which consisted of two histologically and/or immunohistochemically different areas among approximately 450 surgical specimens. Five out of 6 patients were men and the age was ranged between 18 and 61 years old. All these 6 patients presented acromegaly or acrogigantism and hyperprolactinemia was noted in 3 patients. In 2 patients (cases 1 and 2) the two adenomas belonged to different adenoma groups (GH-PRL-TSH group and FSH/LH group), while in the remaining 4 patients (cases 3-6) the two adenomas belonged to the same group (GH-PRL-TSH group). Thus, in all patients at least one of the two adenomas was GH-producing adenoma. Reasons for a high incidence of GH-producing adenomas in surgically resected double pituitary adenomas may include the presence of a variety of histologic subtypes among GH-producing adenomas and the advantage of cytokeratin immunostaining to distinguish these subtypes. In regard to pathogenesis of double pituitary adenomas, adenomas in cases 1 and 2 may be of multicentric occurrence, while those in cases 3-6 may occur through different clonal proliferation within originally one adenoma, resulting in diverse phenotypic expressions. Since there were patients with familial MEN 1 (case 2) and familial pituitary adenoma unrelated MEN 1 (case 3), genetic background should be also considered. Double pituitary adenomas in surgically resected material may not be so infrequent. Further molecular analysis will provide new insights into understanding the pathogenesis of pituitary adenomas and their mechanisms of multidirectional phenotypic diffrentiation.

Collision sellar lesions: experience with eight cases and review of the literature

“…Actually, a significant number of supernumerary pituitary adenomas is likely to remain undiagnosed in surgical series [1]. However, rates as high as 1.3% have been published [2]. The commonest hormone-active adenoma identified in surgical series of double adenomas is GH-secreting adenoma [1, 2], as in our report.…”

“…Given the clinical and imaging similarities to pituitary adenomas, the diagnosis of a dual pathological condition of the sella is usually based on the histological study. To date, very few surgical series have been reported describing specific combinations of sellar lesions like a double pituitary adenoma [1, 2], a combination of an adenoma with RCC [3–5] or a gangliocytoma associated with a pituitary adenoma [6–8]. Mainly, case reports have been published, demonstrating the concomitance of two different pathologies within the sella.…”

Collision Tumors of the Sella: Craniopharyngioma and Silent Pituitary Adenoma Subtype 3: Case Report

“…The same is true of the immunohistochemical and ultrastructural studies key to their evaluation [17][18][19][20].…”

Synchronous GH- and prolactin-secreting pituitary adenomas

“…However, previous reports have also described rare synchronous GH- and prolactin-secreting adenomas (6) (7). In some of these cases, the patients had familial MEN1 syndrome (7). Therefore, a careful family history should be collected in these cases.…”

“…These include dimorphous adenomas composed of GH and prolactin cells, monomorphous mammosomatotrope adenomas (which produce both GH and prolactin), and rarely primitive and often aggressive acidophil stem-cell adenomas (5). However, previous reports have also described rare synchronous GH- and prolactin-secreting adenomas (6) (7). In some of these cases, the patients had familial MEN1 syndrome (7).…”