True hyperprolactinemia in men without visible pituitary adenoma

Area of Science:

• Endocrinology
• Urology
• Radiology

Background:

• Hyperprolactinemia in men can occur without a visible pituitary adenoma on MRI, a condition also known as idiopathic or non-tumoral hyperprolactinemia.
• This presentation is rare, making characterization of such cases important for understanding and management.

Purpose of the Study:

• To characterize a cohort of men diagnosed with hyperprolactinemia despite having normal pituitary imaging on MRI.
• To evaluate the clinical and hormonal characteristics and treatment response in these patients.

Main Methods:

• Retrospective retrieval of clinical and hormonal data from medical records of 13 men with hyperprolactinemia and normal pituitary MRI.
• Assessment of baseline characteristics, response to medical treatment (cabergoline or bromocriptine), and long-term follow-up.

Main Results:

• The mean age at diagnosis was 51 years, with a mean prolactin level of 91 ng/ml.
• Eight men had low baseline testosterone; common presenting symptoms included sexual dysfunction and gynecomastia.
• Medical treatment normalized prolactin and testosterone levels in all patients, leading to clinical improvement in most, with sustained treatment in ten patients after a mean follow-up of 72 months.

Conclusions:

• Symptomatic hyperprolactinemia in men can present with normal pituitary imaging.
• Medical management, primarily with cabergoline, is effective in normalizing hormone levels and improving clinical symptoms in these patients, often without the need for surgery.