Clinically and biochemically silent thyrotroph adenoma with oncocytic change.

A case of clinically and biochemically silent pituitary tumour with ultrastructural and immunohistochemical evidence of thyroid stimulating hormone secretion is presented. Significance of recognition of such silent tumours is discussed.

Ultrastructural study of mixed growth hormone & prolactin secreting pituitary adenomas.

An ultrastructural study was done on 15 mixed growth hormone (GH) and prolactin (PRL)-secreting pituitary adenomas surgically removed from acromegalic patients with hyper-prolactinaemia, in order to see whether the 2 hormones were present in the same cell or in different cells. Double labelling immunogold technique was used for simultaneous ultrastructural localization of GH and PRL. It was found that each neoplastic cell in these 15 tumours (30 to 50 cells were studied in each case) contained 4 populations of granules viz., (i) granules positive for only GH; (ii) granules positive for only PRL; (iii) granules positive for both GH and PRL; and (iv) granules negative for both GH and PRL (unlabelled). Though the relative percentage of these 4 types of granules varied from cell to cell even within the same tumour, the major population (49.9 to 96%) was constituted by the mixed granules showing labelling for both GH and PRL. Almost all the cells examined from each tumour appeared to be mammosomatotrophs. Thus, the study indicated that mammosomatotroph adenomas are perhaps more common among mixed GH and PRL--secreting pituitary adenomas than previously believed. It could be important to recognize these tumours from the therapeutic point of view.

Pituitary adenomas: immunohistochemical: study of 90 cases.

Pituitary tumors from 90 patients were investigated using immunohistochemical study and the results were correlated with clinical records. There were 32 benign prolactinomas and two malignant counterparts, 13 growth hormone positive tumors. 10 corticotropic adenomas, and 10 gonadotropic tumors. Four tumors showed positivity for both prolactin and growth hormone, one prolactin and gonadotropin. An example of mixed, luteinizing hormone, prolactin and growth hormone was observed. Additionally, there was an adenoma composed of two compartments secreting prolactin and growth hormone. One patient had a recurrent gonadotropin adenoma after surgical removal of the original prolactinoma. Fifteen tumors were negative for all hormones and most were nonfunctioning clinically. The clinicopathologic correlations were found to be good for prolactinoma, growth hormone positive tumors and for tumors producing both prolactin and growth hormones causing a combined feature of hyperprolactinemia and acromegaly.