[Influence of hyperprolactinemia and tumoral size in the postoperative pituitary function in clinically nonfunctioning pituitary macroadenomas].

OBJECTIVE: To study the influence of hyperprolactinemia and tumoral size in the pituitary function in clinically nonfunctioning pituitary macroadenomas.

METHODS: Twenty three patients with clinically nonfunctioning pituitary macroadenomas were evaluated by image studies (computed tomography or magnetic resonance) and basal hormonal level; 16 had preoperative hypothalamus-hypophysial function tests (megatests). All tumors had histological diagnosis and in seventeen immunohistochemical study for adenohypophysial hormones was also performed. Student's t test, chi square test, exact test of Fisher and Mc Neman test were used for the statistics analysis. The level of significance adopted was 5% (p<0.05).

RESULTS: Tumoral diameter varied of 1.1 to 4.7 cm (average=2.99 cm +/- 1.04). In the preoperative, 5 (21.7%) patients did not show laboratorial hormonal deficit, 9 (39.1%) developed hyperprolactinemia, 13 (56,5%) normal levels of prolactin (PRL) and 1 (4.3%) subnormal; 18 (78.3%) patients developed hypopituitarism (4 pan-hypopituitarism). Nineteen patients (82.6%) underwent transsfenoidal approach, 3 (13%) craniotomy and 1 (4.4%) combined access. Only 6 patients had total tumoral resection. Of the 17 immunohistochemical studies, 5 tumours were immunonegatives, 1 compound, 1 LH+, 1 FSH +, 1 alpha sub-unit and 8 focal or isolated immunorreactivity for one of the pituitary hormones or sub-units; of the other six tumours, 5 were chromophobe and 1 chromophobe/acidophile. No significant statistic difference was noted between tumoral size and preoperative PRL levels (p=0.82), nor between tumoral size and postoperative hormonal state, except in the GH and gonadal axis. Significant statistic was noted: between tumoral size and preoperative hormonal state (except in the gonadal axis); between normal PRL levels, associated to none or little preoperative hypophysial disfunction, and recovery of postoperative pituitary function.

CONCLUSION: Isolated preoperative hyperprolactinemia and tumoral size have not been predictable for the recovery of postoperative pituitary function.