ACTA ENDOCRINOLOGICA (BUC)

We present the case of a 29 years young man with acromegaly caused by a plurihormonal pituitary adenoma expressing GH, PRL, FSH and TSH within the tumoral cells. Immunoassays showed a high serum level of GH and PRL, and a serum level within normal ranges for FSH, TSH and LH. Tumoral immunohistochemistry (avidin biotin technique) was positive for GH, PRL and TSH. The presence and colocalisation of GH and FSH was shown by immunelectronmicroscopy with double immunogold techniques. The gold particles (sizes 10 nm for GH and 15 nm for FSH) were colocalised within the same translucent secretory granules of some tumor cells, ultrastructurally similar to gonadotroph cells, aside from other tumor somatotroph cells with dense secretory granules and only 10 nm antiserum GH gold particles. High cerebrospinal fluid (CSF) levels of FSH and a high ratio of CSF/serum FSH concentrations, above 1, were the first indicators that revealed, before pituitary surgery, that FSH is secreted from the pituitary tumor. TSH was a “mute” hormone, without biochemical or clinical expression outside the tumor. This pituitary adenoma showed a good response to surgery and to conventional high voltage conformational radiotherapy with the usual dose of 50 Gy. Bromocriptine and Octreotide, but not the gonadotropin releasing hormone agonist (Triptorelin), produced additional beneficial effects. It is tempting to suggest a somatogonadotroph cell as precursor of this pituitary tumor.