At least one fifth of pituitary adenomas exhibit plurihormonality when using immunohistochemistry for anterior pituitary hormones. However, the correlation with clinical features is weak, without an agreement upon pathological predictors of tumour behaviour.
The aim was to determine the immunoreactivity for anterior pituitary hormones and alpha subunit in 276 consecutive pituitary adenoma patients, aged 2279 years (44.3±8), 154 F/ 122 M: 83 acromegalics (ACM), 173 nonfunctioning adenomas (NFA) and 20 prolactinomas (PRM) submitted to surgery via transfrontal (81) or transsfenoidal (195) way along 10 years (19952005). In addition, clinical data, hormonal secretion and tumour size were evaluated before pituitary surgery. Local ethical committee approved the study design. The immunoreactivity performed by the avidin-biotin-complex method was evaluated for beta FSH, LH, TSH, alpha subunit, PRL and GH, using a semiquantitative scale of stained cells: strong (>20%), positive (1020%), weak (510%) and negative (<5%). CT or MRI tumor size (under 1 cm, 12 cm, 24 cm and over 4 cm on maximal diameter) were considered together with the Hardy neuroradiological stage. The results showed that 16/83 ACM, 53/173 NFA and 4/20 PRM exhibited immunoreactivity for beta FSH and LH. Tumour size in the gonadotrophin - positive group (> 10% of stained cells) was between 12 cm in 6 ACM, 21 NFA and 2 PRM, while positive bigger tumours (24 cm) were in 7 ACM, 24 NFA and 2 PRM. Giant, over 4 cm tumours were positive in 3 ACM, 8 NFA and no PRM. A similar trend of the tumour size distribution was observed in the monohormonal or null cell adenomas.
In conclusion, tumour size and gonadotrophin plurihormonality are independent factors in the management of pituitary adenomas.
01 - 05 Apr 2006
European Society of Endocrinology