Hauache Omar M, Rocha Antonio J, Maia Antonio C M, Maciel Rui M B, Vieira José Gilberto H
Department of Endocrinology, Fleury Diagnostic Center, São Paulo, Brazil.
Clin Endocrinol (Oxf). 2002 Sep;57(3):327-31. doi: 10.1046/j.1365-2265.2002.01586.x.
Hyperprolactinaemia is caused by high levels of monomeric, dimeric or macro forms of prolactin in circulation, the monomeric form being predominant in patients with prolactinomas. Macroprolactinaemia, however, is common and is associated with asymptomatic cases. In this study, we reviewed our records regarding clinical and imaging investigations in patients who were found to have hyperprolactinaemia predominantly due to the presence of macroprolactin and compared them with the findings observed in patients whose prolactin molecular size consisted predominantly of the monomeric form.
We conducted a retrospective study of 113 consecutive patients (nine men and 104 women, aged 19-67 years, median age 39 years) with hyperprolactinaemia who were screened for the presence of macroprolactin by polyethylene glycol precipitation and/or chromatography and submitted to pituitary magnetic resonance imaging (MRI) and/or computerized tomography (CT).
Fifty-two of 113 patients (46%) had hyperprolactinaemia due to macroprolactin, whereas the remaining 61 patients (54%) had their hyperprolactinaemia confirmed by the predominance of the monomeric form. Both groups shared similar mean prolactin levels (79.9 +/- 63.6 micro g/l, median of 62.0 micro g/l, and 97.9 +/- 155.4 micro g/l, median of 61.0 micro g/l, respectively). Of the patients with macroprolactinaemia, 46% had no symptoms of hyperprolactinaemia, whereas only 10% of the patients who screened negative for macroprolactin were asymptomatic. There was an association between macroprolactinaemia and negative pituitary imaging findings: normal pituitary images were found in 78.9% of patients who had macroprolactinaemia and in 25% of patients with monomeric hyperprolactinaemia. In addition, none of the patients with macroprolactinoma (seven cases) had macroprolactinaemia.
The presence of macroprolactinaemia does not exclude the possibility of a pituitary adenoma and consequently may not prevent pituitary imaging studies. However, our data demonstrate that all asymptomatic patients who screened positive for macroprolactin had normal pituitary imaging studies. Patient samples showing hyperprolactinaemia should be first tested for macroprolactin, before the patient is submitted to imaging studies. We suggest that imaging studies should be ordered in patients with macroprolactinaemia when indicated by clinically relevant features. As a result, unnecessary anxiety and costly medical procedures may be prevented.
高催乳素血症是由循环中高水平的单体、二聚体或大分子形式的催乳素引起的，在催乳素瘤患者中单体形式占主导。然而，大分子催乳素血症很常见，且与无症状病例相关。在本研究中，我们回顾了关于主要因大分子催乳素而被发现患有高催乳素血症患者的临床和影像学检查记录，并将其与催乳素分子大小主要由单体形式组成的患者的检查结果进行比较。
我们对113例连续的高催乳素血症患者（9名男性和104名女性，年龄19 - 67岁，中位年龄39岁）进行了一项回顾性研究，这些患者通过聚乙二醇沉淀和/或色谱法筛查大分子催乳素的存在，并接受了垂体磁共振成像（MRI）和/或计算机断层扫描（CT）检查。
113例患者中有52例（46%）因大分子催乳素导致高催乳素血症，而其余61例患者（54%）的高催乳素血症通过单体形式占主导得以证实。两组的平均催乳素水平相似（分别为79.9±63.6μg/L，中位数为62.0μg/L，以及97.9±155.4μg/L，中位数为61.0μg/L）。在大分子催乳素血症患者中，46%没有高催乳素血症的症状，而大分子催乳素筛查为阴性的患者中只有10%无症状。大分子催乳素血症与垂体影像学检查阴性结果之间存在关联：在大分子催乳素血症患者中有78.9%的垂体图像正常，而在单体形式高催乳素血症患者中有25%的垂体图像正常。此外，所有大分子催乳素瘤患者（7例）均无大分子催乳素血症。
大分子催乳素血症的存在并不排除垂体腺瘤的可能性，因此可能无法避免垂体影像学检查。然而，我们的数据表明，所有大分子催乳素筛查呈阳性的无症状患者的垂体影像学检查均正常。在患者接受影像学检查之前，对于显示高催乳素血症的患者样本应首先检测大分子催乳素。我们建议，当有临床相关特征提示时，应对大分子催乳素血症患者进行影像学检查。因此，可以避免不必要的焦虑和昂贵的医疗程序。
