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[Prolactinoma in man: clinical and histological characteristics]
J Trouillas1, E Delgrange, E Jouanneau
1Laboratoire d'Histologie et Embryologie moléculaires, unité INSERM U433, Faculté de médecine Lyon-RTH Laennec, 69372 Lyon cedex 08, France.
Abstract:
Prolactinoma usually occurs a small intrasellar tumor in women or as a large tumor in men. To determine whether the predominance of macroprolactinomas in men is due to a delay in diagnosis as has been suggested, or whether there is a sex-related difference in growth rate we conducted a retrospective study in 45 men and 51 women with prolactinomas. Preoperative prolactin level (PRL) was 2,789 573 ng/ml and mean tumor size was 26 2 mm. Prolactin levels and tumor size were significantly higher in women (292 74 ng/ml and 10 1 mm; p<0.01). There was no correlation with age at diagnosis or duration of symptoms. Giant tumors were only observed in men (n=8). Frequency of resistance to bromocriptine (30% vs 5%, p<0.01) and invasive tumors (52% vs 27%, p<0.001) were significantly higher in men than in women. Likewise, proliferation rate was higher for the prolactinomas in men (Ki-67: 2.6 1.1% positive nuclei vs 0.4 0.2%; p=0.08; PCNA: 5.0 2.3% vs 3.7 1.1%). In conclusion, prolactinomas in men are more aggressive than in women. They grow rapidly, often invade the cavernous sinus and are resistant to bromocriptine; proliferation rates can be increased.
Insights
Prolactinomas in men are more aggressive, growing faster and invading more often than in women. These male prolactinomas show higher resistance to bromocriptine treatment.
Area of Science:
- Endocrinology
- Oncology
- Neurosurgery
Background:
- Prolactinomas, pituitary tumors secreting prolactin, typically present as small tumors in women and large tumors in men.
- The higher incidence of macroprolactinomas in men suggests potential differences in diagnosis timing or tumor biology.
Purpose of the Study:
- To investigate sex-related differences in prolactinoma growth rate and aggressiveness.
- To determine if macroprolactinoma predominance in men is due to delayed diagnosis or inherent sex-based growth differences.
Main Methods:
- Retrospective study of 45 men and 51 women diagnosed with prolactinomas.
- Analysis of preoperative prolactin levels, tumor size, resistance to bromocriptine, tumor invasiveness, and proliferation markers (Ki-67, PCNA).
Main Results:
- Men presented with significantly larger tumors and higher prolactin levels compared to women.
- Giant prolactinomas were exclusively observed in men.
- Men exhibited higher rates of bromocriptine resistance (30% vs 5%) and tumor invasiveness (52% vs 27%).
- Proliferation rates (Ki-67, PCNA) were notably higher in male prolactinomas.
Conclusions:
- Prolactinomas in men are characterized by more aggressive behavior, including rapid growth and increased invasiveness.
- Male prolactinomas demonstrate a higher frequency of resistance to bromocriptine therapy.
- These findings suggest intrinsic sex-related differences in prolactinoma aggressiveness rather than solely delayed diagnosis in men.