A Somatotropin-Producing Pituitary Adenoma Concomitant with an Isolated Adrenocorticotropin-Producing Pituitary Adenoma with a Left Adrenal Tumor

Presentation Number: SUN-0781
Date of Presentation: June 22nd, 2014

Yuki Kobayashi*1, Masahiro Takei2, Keiko Takeshige3, Yousuke Ohkubo2, Mieko Kumagai2, Teiji Takeda4, Mitsuhisa Komatsu2 and Satoru Suzuki5
1Shinshu University School of Medicine, Matsumoto-shi, Japan, 2Shinshu University, Schoolo of Medicine, Matsumoto-shi, Japan, 3Shinshu University School of Medicine, Matsumoto-shi, 4Shinshu University, Matsumoto-Shi, Japan, 5Fukushima Medical University, Fukushima-shi, Japan

Abstract

Clinical background: The prevalence of double pituitary adenomas, confirmed by autopsy and from surgical materials, is approximately 1% (1). In most cases, there is only one tumor that contains two different lesions contiguously in each tumor. Independent double pituitary adenomas with distinct hormonal features are very rare.

Case: A 67-year-old woman was admitted to our hospital because of acromegalic appearance. Laboratory data revealed a serum GH level of 4.6 ng/ml and serum insulin-like growth factor-1 level of 811 ng/ml. Oral glucose tolerance test showed no suppression of GH values. Endocrine examination showed a lack of circadian rhythmicity of ACTH and cortisol. Serum cortisol level was not suppressed by 0.5 mg of dexamethasone. Whereas the result of high dose dexamethasone suppression test was marginal. The response of ACTH and cortisol after corticotropin-releasing hormone stimulation was normal. Gadolinium enhanced magnetic resonance imaging revealed two isolated adenomas in the pituitary. These findings strongly suggested a diagnosis of acromegaly with subclinical Cushing’s disease. Transsphenoidal surgery was performed. Hematoxylin and eosin staining showed that the left and right adenomas were composed of basophilic and acidophilic cells, respectively. Immunohistochemical staining showed the left adenoma to be positive for ACTH and negative for GH. In contrast, the right adenoma was GH-positive and ACTH-negative.

Clinical lessons: Double pituitary adenomas are rare. In most cases, there is one tumor that contains two different lesions contiguously in each tumor, and independent double pituitary adenomas with distinct hormonal features are extremely rare. This is a rare case report of a combination of GH-producing adenoma (ACTH negative) and isolated ACTH-producing adenoma (GH-negative). We have also reviewed previous reported double pituitary adenomas and discussed functionality of the left adrenal tumor.

 

Nothing to Disclose: YK, MT, KT, YO, MK, TT, MK, SS