Summary
Difficulties and controversies still exist in the diagnosis of small (3-5 mm) prolactinomas
(micro-PRL-omas). In the present study serum prolactin (PRL) was assayed in 4199 women
aged 14-43 years belonging to 4 groups: A: 753 women with normal cycles (NC) and infertility
(control group), B: 2523 with menstrual disorders, C: 519 with NC and hirsutism, D:
404 with galactorrhoea. The distribution of PRL values from 1 to 30 ng/ml was almost
similar in the subjects of group A, B and C. Within this range the vast majority of
subjects (91%, 92.2% and 88% respectively in these 3 groups and 83% in group D) had
PRL levels from 1 to 15 ng/ml and together with the proportion of subjects with PRL
values 16 to 20 ng/ml they included 96.7% of the entire mixed population. A proportion
of scattered outlying PRL values above 30 ng/ml was found in each group (A = 2%, B
= 3%, C=l% and D = 28.7%) and in this subset 117 prolactinomas (PRL-omas) were found,
19 (23%) in the 83 subjects with PRL levels 31-49 ng/ml and 98 (75.3%) in the 130
subjects with PRL values ≥ 50 ng/ml. Of the 117 PRL-omas 9 were bigger than 10 mm
and 4 had a size from 6 to 9 mm. In the remaining 104 the size was presumed from direct
or indirect radiological evidence to be 3-5 mm. The age of the patients ranged from
14-43 yrs with a greater prevalence of the younger ages (38% consulted and 56.5% manifested
their symptoms before the age of 26 yrs). Provocative tests performed in 37 patients
and in 37 subjects with non-tumorous hyperPRL-aemia (NT-HyperPRL) gave ambiguous results
when basal PRL ranged from 30 to 49 ng/ml but the response was negative in all cases
with micro-PRL-oma and in the majority of cases with NT-HyperPRL when basal PRL was
50-100 ng/ml. Independently of PRL levels, the patients with micro-PRL-omas presented
with all the spectrum of menstrual disorders. Secondary amenorrhoea was the most common
symptom (46%). Thirteen patients (12.5%) presenting with menses of normal length had
PRL varying from 30 to 100 and in one case up to 230 ng/ml. Galactorrhoea was found
in 63.5% of the patients with micro-PRL-omas. However, 1/3 of the patients with high
PRL levels (> 50 ng or > 100 ng) did not have spontaneous or provoked galactorrhoea
at the time of the examination.
Key words
Microprolactinomas - Prolactin Levels