Precocious puberty in a boy with a PRL-, LH- and FSH-secreting pituitary tumour: hormonal and immunocytochemical studies.

The case of a 7-year-old boy affected with precocious puberty and a large intra- and suprasellar pituitary tumour is described. He had hyperprolactinemia and elevated serum LH, FSH and testosterone concentrations. Pre-operative dynamic hormonal studies showed a rise of PRL, LH and FSH levels after TRH (200 micrograms iv) and a rise of LH and FSH after GnRH (100 micrograms iv). Dopamine infusion (4 micrograms.kg-1.min-1 for 180 min) did not affect gonadotropins and greatly reduced serum PRL. GnRH analogue (buserelin, 0.5 mg sc t.i.d. for 10 days) administration inhibited both LH and FSH, but did not affect PRL concentration. Serum LH and FSH increased after ethinyl-estradiol (0.5 mg orally) administration, and were not affected by bromocriptine (5-7.5 mg/day for 10 days), which decreased serum PRL levels. The patient underwent transfrontal neurosurgery and a large tumour mass was completely removed. Morphological study of the excised tumour, by electron microscope double label immunotechnique, revealed that a large number of tumour cells (70-85%) were positive for PRL, LH and FSH, co-localized in the same secretory granule. After neurosurgery, serum PRL, LH, FSH and testosterone levels fell to within the normal limits. Two months later the patient was well and signs of precocious puberty had partially regressed; hormone levels were in the normal range and MR imaging control did not demonstrate any residual lesion in the sellar region.