Differences in pathological findings and growth hormone responses in patients with growth hormone-producing pituitary adenoma.
Plasma growth hormone (GH) responses to various stimuli were examined in 21 patients with GH-producing pituitary adenomas, classified into three types by the immunohistochemistry of cytokeratin and the glycoprotein hormone alpha-subunit distribution. Seven type 1 adenomas were exclusively composed of cells in which the cytokeratin formed a dot-like pattern; they were chromophobic to hematoxylin and eosin (H&E), occasionally positive for GH, and almost completely negative for the alpha-subunit. Thirteen type 2 adenomas were composed of cells with cytokeratin that had a perinuclear distribution; they were eosinophilic to H&E, and diffusely positive for both GH and the alpha-subunit. One patient had a type 3 adenoma which had a mixed pattern of intracellular cytokeratin distribution and was chromophobic and eosinophilic to H&E. Clinically, type 1 is characterized by earlier onset, larger tumor size, and more frequent aggressive extension. Paradoxical GH responses to TRH and OGTT were seen in 1 of 6 patients (16.7%) of type 1 and 8 of 9 patients (88.9%) of type 2, and 0% of type 1 and 62.5% of type 2, respectively. Type 2 cases showed higher plasma GH response to GH-releasing hormone, and a tendency to greater suppression of plasma GH by bromocriptine compared with type 1. Octreotide acetate administration revealed that the nadir/basal ratio of plasma GH levels was 42.9 +/- 6.6% in type 1 and 13.5 +/- 5.8% in type 2. These results suggest that there is a pathophysiological difference between these two distinct types of GH-producing pituitary adenomas.
Bando
H
H
Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
Sano
T
T
Ohshima
T
T
Zhang
C Y
CY
Yamasaki
R
R
Matsumoto
K
K
Saito
S
S
D000236:Adenoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D005260:Female; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D011388:Prolactin / Q000097:blood; D011859:Radiography
D011388:Prolactin; D013006:Growth Hormone