Immunohistochemical demonstration of oncocytes in nongonadotrophic pituitary adenomas.
An immunohistochemical study to demonstrate oncocytes in nongonadotrophic pituitary adenomas was performed. The adenomas were 10 prolactinomas, 2 ACTH-producing adenomas (ACTHomas), and 28 growth hormone-producing adenomas (GHomas); we also studied 5 pituitary oncocytomas. GHomas were divided into two groups: GHomas with (GHomas-1) and without (GHomas-2) fibrous bodies. A small number of solitary large cells showed intense cytoplasmic granular reactivity for mitochondrial protein and cytochrome oxidase, resembling oncocytes in oncocytomas. The proportions of the mitochondrial protein-positive cells ranged from zero to 2.1% (0. 3+/-0.4%). They were more frequent in GHomas, GHomas-1 in particular, than other types of adenomas (P<0.01), and were mostly negative in prolactinomas and ACTHomas. In multivariate analysis, the proportions showed positive correlation with age (P<0.01) and the Ki-67 (MIB-1) labeling index (P<0.01) and tended to increase in number with recurrence (P<0.05). In GHomas, these cells were more common in cases with low basal GH level (P<0.01) and large tumor volume (P<0.01). We consider that these cells represent oncocytes existing in varying numbers in adenomas. We suggest that oncocytic change in nongonadotrophic adenomas indicates poor differentiation and/or some aggressiveness, which lead to a decrease in the endocrine activity of the tumor.
Nishioka
H
H
Department of Neurosurgery, Tokyo Medical University, 6-7-1 Nishi-shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
Ito
H
H
Hirano
A
A
D000236:Adenoma / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D018249:Adenoma, Oxyphilic / Q000737:chemistry / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D004847:Epithelial Cells / Q000737:chemistry / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000737:chemistry / Q000473:pathology; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*