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Ultrastructural differences in the endoplasmic reticulum among various pituitary tumor types
Author(s) -
Sharma Soniya,
Rotondo Fabio,
Kovacs Kalman,
Horvath Eva
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.565.18
Subject(s) - endoplasmic reticulum , ultrastructure , prolactin , prolactin cell , biology , pathology , pituitary tumors , somatotropic cell , endocrinology , medicine , pituitary gland , hormone , microbiology and biotechnology
Our aim was to reveal ultrastructural differences in the endoplasmic reticulum (ER) among surgically removed human pituitary tumors. More than 2000 pituitary tumors were studied by electron microscopy. In growth hormone (GH) adenomas, the ER is well developed and consists mainly of rough surfaced endoplasmic reticulum (RER) and few ER membranes without ribosomes, called smooth surfaced endoplasmic reticulum (SER). In the sparsely granulated GH adenomas, the ER is less prominent and is seen in fibrous bodies containing keratin immunopositive microfilaments. In prolactin (PRL) adenomas, the RER is conspicuous, forming concentric whorls. In adenocorticotropin (ACTH) and thyroid stimulating hormone (TSH) adenomas, the ER and consists of RER and to a lesser extent, SER. In gonadotroph adenomas and null cell adenomas, the ER is poorly developed. In GH adenomas exposed to somatostatin analogs and in prolactin adenomas exposed to dopamine agonists, regression of ER is noted. In pituitary carcinomas, the ER is recognizable but it is less extensive than in the benign neoplasms. In conclusion, the ultrastructural investigation of ER provides valuable information on the cytogenesis and cellular composition of pituitary tumors. There is also a mild correlation between endocrine activity and extent of ER. However, no correlation exists between invasive and non‐invasive tumors and growth potential. Pituitary carcinomas cannot be distinguished from benign adenomas based on the ultrastructural features of ER.