A 27-year-old man present with complaints of loss of libido and erectile dysfunction since a year. On questioning, he gives history of headache, dull aching, global, not associated with nausea or vomiting, usually relieved by painkillers, present on 5 days a week. He has also noticed that sometimes he bumped into objects on his sides while walking. He has also noticed constipation and weight gain. On examination, he is 160 cm tall with a BMI 25 kg/m2. Blood pressure 110/70 mm of Hg, no postural drop. Confrontation test reveals bilateral temporal hemianopia. Testicular volume 15 mL soft bilateral. No galactorrhea is elicited. Ankle jerks delayed. Laboratory investigations are as follows: Hemoglobin 10.5 g/dL, normocytic normochromic anemia. Testosterone 100 ng/dL, LH 0.01 IU/L, FSH 0.01 IU/L, TSH 2 microIU/L, free T4 0.68 ng/dL. Cortisol 2.8 mg/dL. Prolactin 47 ng/mL from one lab and 1780 ng/mL from another lab. Automated perimetry reveal bitemporal hemianopia. Magnetic resonance imaging of the hypothalamic pituitary region reveals 2.4 cm tall, pituitary mass with suprasellar extension with compression of the optic chiasm without parasellar extension. A diagnosis of pituitary macroadenoma probably macroprolactinoma with hypopituitarism is made.
Why is there no galactorrhea despite elevated prolactin levels in this patient?
Medicine
Only 35% of men with prolactinomas have galactorrhea as the male mammary tissue is less susceptible to lactogenic effect of hyperprolactinemia. Even in women only 50% have galactorrhea as the lactogenic effect is seen in oestrogen primed mammary tissue. So if the patient has been hypogonadal for a long duration, there may be no galactorrhea.
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