Endocrine Abstracts

Hyperprolactinemia is one of the most common problems in clinical endocrinology. It relates with various etiologies (physiological, pharmacological, pathological), the clarification of which requires careful history taking and clinical assessment.

We present the case of a 15-year-old girl, with history of secondary amenorrhea and headache in the presence of mildly elevated prolactin level, diagnosed as a microprolactinoma on MRI scan (4–5 mm) and treated with cabergoline (1 mg/week) for 2 years. At presentation she had resumed menses with low prolactin. Cabergolinewas stopped for 5 months,while she remained asymptomatic, with monthly menstrual cycles induced by progesterone. Biochemistry revealed: normal thyroid function tests, hyperprolactinemia: 4 × ULN (1229 uUI/ml) with equivocal reduction after PEG-47%), normal estradiol, low gonadotropes, normal IGF-1, normal urinary free cortisol, normal 17-(OH) progesterone and normal testosterone level. Pelvic ultrasound showed normal aspect of the ovaries. Sequential Pituitary MRI (2017): incidentaloma 4–5 mm; 2018: microadenoma (5–6 mm), (2019) stationary lesion of 7 mm after 2 yrs of cabergoline. The etiology of the elevated prolactin and of the secondary amenorrhea is challenging in this case, also the need of cabergoline treatment. Most guidelines propose in case of normal prolactin levels and no visible tumor remnant on MRI, after 2 years of low dose cabergoline, to try to stop medication. In this case, the presence of stationary, but visible pituitary microadenoma on MRI and resumed hyperprolactinemia after cabergoline cessation, could be indicative of either stress induced or tumor-secreting PRL, but there is no clear cut-off value of serum PRL level that could be usedto distinguish between them. Dimitriadis G et al. proposed the cutoff of PRL level exceeding 85.2 ng/ml in women with PCOS that is suggestive of a PRL -producing adenoma. In addition, pituitary MRI could be justifiable in young PCOS patients with milder PRL elevation, low LH levels and concomitant symptoms suspicious of a pituitary adenoma (Dimitriadis G, Angelousi A, Mehta H, Shad A, Mytilinaiou M, Kaltsas G, et al. The value of PRL in predicting prolactinoma in hyperprolactinemic PCOS. European Journal of Clinical Investigation. 2018;48:e12 961). In our case,the absence of PCOS criteria is limiting our possibilities to use this threshold. We will discuss the differential diagnosis and management of this unusual case.