Thyroid Research and Practice

CASE REPORT
Year
: 2018  |  Volume : 15  |  Issue : 2  |  Page : 94--95

Galactorrhea and reversible pituitary hyperplasia in primary hypothyroidism


Mansoor C Abdulla 
 Department of General Medicine, MES Medical College, Malappuram, Kerala, India

Correspondence Address:
Mansoor C Abdulla
Department of General Medicine, MES Medical College, Perinthalmanna, Malappuram - 679 338, Kerala
India

Abstract

Long-standing hypothyroidism causing thyrotroph hyperplasia can result in enlargement of the pituitary gland and hyperprolactinemia. A 20-year-old unmarried girl presented with galactorrhea for 4 months. She was evaluated and diagnosed to have severe hypothyroidism resulting in hyperprolactinemia and reversible pituitary hyperplasia. This case helps the clinicians to be aware of an unusual presentation of severe primary hypothyroidism and reminds to consider it in the differential diagnosis of pituitary enlargement with mild hyperprolactinemia.



How to cite this article:
Abdulla MC. Galactorrhea and reversible pituitary hyperplasia in primary hypothyroidism.Thyroid Res Pract 2018;15:94-95


How to cite this URL:
Abdulla MC. Galactorrhea and reversible pituitary hyperplasia in primary hypothyroidism. Thyroid Res Pract [serial online] 2018 [cited 2022 Dec 2 ];15:94-95
Available from: https://www.thetrp.net/text.asp?2018/15/2/94/236705


Full Text



 Introduction



Hyperprolactinemia has various causes including prolactinoma and iatrogenic. Severe primary hypothyroidism can result in hyperprolactinemia secondary to pituitary stimulation by thyrotropin-releasing hormone and can even result in reversible pituitary hyperplasia. Pituitary enlargement secondary to primary hypothyroidism is an uncommon occurrence, and the reactive pituitary gland enlargement may be difficult to differentiate from inflammatory disorders as well as from functional pituitary adenomas.

 Case Report



A 20-year-old unmarried girl presented with galactorrhea for 4 months. She did not have any medical illness in the past and had no history of intake of any drugs causing hyperprolactinemia. She attained menarche at the age of 13 years. She had regular menstrual cycles with normal duration and amount of flow. Neurological examination was normal and had no visual field defects. Prolactin level was 24.8 ng/ml (normal range 3.7–17.9 ng/ml). Thyroid-stimulating hormone was high (>100 mIU/L) and free T4 low (0.4 ng/dl) and free triiodothyronine were normal. Anti-thyroid peroxidase antibody level was 920 U/mL (normal range 11–210 U/mL). Adrenocorticotropic hormone, luteinizing hormone, and follicle-stimulating hormone levels were normal. Magnetic resonance imaging of the brain showed a sellar lesion measuring 1.1 cm × 1 cm × 1.2 cm which was mildly hyperintense in T2-weighted sequence with homogeneous enhancement after the administration of gadolinium and mildly protruding into the suprasellar region [Figure 1]a and [Figure 1]b. Levothyroxine therapy was started at a dose of 100 μg/day. At 3 months of treatment, galactorrhea reduced and a review magnetic resonance imaging brain after 8 months showed resolution of the pituitary lesion. A repeat serum prolactin level was 15.0 ng/ml (normal range 3.7–17.9 ng/ml) at the end of 8 months treatment.{Figure 1}

 Discussion



Long-standing hypothyroidism causing thyrotroph hyperplasia may cause expansion of the sella turcica and the pituitary gland.[1] The low levels of T4 induce a compensatory increase in thyroid-releasing hormone secretion from the hypothalamus, which stimulates synthesis of not only thyroid-stimulating hormone but also prolactin from the anterior pituitary. Pituitary cells even have a decreased sensitivity to the inhibitory action of dopamine possibly at receptor or postreceptor levels. 3,5,3' triiodothyronine may decrease prolactin mRNA levels in pituitary cells. Therefore, reduced thyroid hormone levels will lead to more prolactin synthesis.[2] Prolactin clearance from the circulation is also decreased in hypothyroidism.[3] Regression of pituitary hyperplasia has been shown to occur following adequate treatment of the primary hypothyroidism with hormone replacement.[4],[5] Our patient presented with galactorrhea and had no other features of hypothyroidism. This case helps the clinicians to be aware of such unusual presentation of severe primary hypothyroidism and reminds to consider it in the differential diagnosis of pituitary enlargement with mild hyperprolactinemia. Levothyroxine replacement can normalize both hormone levels and pituitary hyperplasia avoiding unnecessary treatments (dopamine agonist) or even surgical interventions.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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