下垂体腺腫のうち成長ホルモンとプロラクチン産生腫瘍は一般的にはpure growth hormone secreting adenoma(PGA), pure prolactin secreting adenoma(PPA)とmixed growth hormoneprolactin secreting adenoma(MGPA)に分類されている.更に詳細に分類するとMGPAはacidophil stem cell adenoma(ASCA), mammosomatotroph adenoma(MSA),およびmixed somatotroph-lactotroph adenoma(MSLA)に分けられている。ASCAとMSAは両ホルモンを持っている細胞からなる腫瘍で,MSLAは両ホルモンをそれぞれ別々の細胞が産生している腫瘍といわれている.今回30例の下垂体腺腫の手術例についてこのような詳細な検討をするため,両ホルモンの細胞内分布について二重標識蛍光抗体法を行い共焦点レーザー顕微鏡(CLSM)で観察し検討した.プロラクチン産生腫瘍とされた10例ではPPAが8例,MSLAが2例であった.成長ホルモン産生腫瘍の10例ではMSLAは3例,MSAは4例,PGAが3例であった.非機能性腫瘍の10例では両ホルモンとも認められぬもの5例,PGAが2例,PPA,MSA,MSLAが1例ずつであった.これらの結果よりプロラクチン産生腫瘍ではPPAが多いが,成長ホルモン産生腫瘍ではMGPAが多く,そのうちでもMSAが大部分を占めていることがわかった.CLSMによる下垂体腺腫の観察の報告は今までなく,分泌穎粒の細胞内分布などもよく見え,二重染色による観察も簡便であり,下垂体腺腫の詳細な分類に役立つことがわかった.We retrospectively studied 30 pituitary adenomas to determine the intracellular distributions of prolactin (PRL) and growth hormone (GH) on the same section by double immunofluorescence staining and subsequent observation by confocal laser scanning microscopy (CLSM). The clinical presentations of these tumors were hyperprolactinemia (10 cases), acromegaly (10 cases), and nonfunctioning (10 cases). Of the 10 cases of hyperprolactinemia, 8 were pure PRL- secreting adenomas and 2 were mixed somatotroph-lactotroph adenomas (MSLA). Of the 10 cases of acromegaly, 3 were MSLA, 4 were mammosomatotroph adenomas (MSA), and 3 were pure GH-secreting adenomas. Among the 10 nonfunctioning tumors, there were 2 pure GH-secreting adenomas, one pure PRL-secreting adenoma, one MSA, one MSLA, and 5 negative cases for both PRL and GH. We conclude that pituitary adenomas with clinical hyperprolactinemia are mostly pure PRL-secreting adenomas, whereas those with acromegaly are mostly mixed PRL-GH-secreting adenoma. In addition, pituitary adenomas without clinical endo-crinopathy have diverse hormonal expressions. The method we used in this study by CLSM is technically easy and thus can be performed on a routine basis for more definite classifications of pituitary adenomas
