Interrelationships between tumour size, age, plasma growth hormone and incidence of extrasellar extension in acromegalic patients

Abstract

Abstract. In 44 consecutive acromegalic patients we studied the interrelationships between tumour size, age, incidence of extrasellar extension, growth hormone levels and 'tumour growth'. These parameters were compared with results from a previous study in 62 prolactinoma patients. It appeared that the incidence of extrasellar extension in acromegalic patients was lower than in the prolactinoma patients (32 versus 44%). In acromegalic patients extrasellar extension occurred on the average at a lateral sellar and tumour area of almost 1 cm2 larger than in prolactinoma patients (with respect to sellar size generally above 3 cm2 versus 2 cm2, with respect to tumour size generally above 4 cm2 versus 3 cm2). Log tumour size and log basal growth hormone level were positively correlated (P < 0.0005). In the acromegalic patients there was a negative correlation between the size of the pituitary tumour and the age of the patient (P < 0.005) in contrast to the absence of such a relationship in the prolactinoma patients. In the group of acromegalic patients mean tumour size decreased gradually from the third to the sixth decade (5.0, 3.8, 3.0 and 2.3 cm2, respectively). The interval between the time of appearance of symptoms and the time of diagnosis was significantly shorter in younger patients and in women. The restriction of large tumours (lateral area > 5 cm2) to young patients (< 35 year) and the short period between the appearance of symptoms and the time of diagnosis in these patients indicate that growth hormone secreting pituitary tumours generally grow more rapidly in younger patients.