LORI.caprine

Adrenal adenoma causing lactation in a male

Keywords: lactation, male, adrenal, adenoma.

A six year old Toggenburg wether (castrated male) was presented with clinical signs of lactation. During 8 days of observation, 250 ml of milk was produced on the first day but daily production thereafter varied between 2 and 20 ml. The secretion had the appearance of normal milk with a somatic cell count of 1,380,000/ml (normal range for goats: 282,500 to 1,660,000 cells/ml). The milk protein content was 2.7%, fat 1.7% and lactose 2.3% (approximately 65%, 40%, and 55% of the respective normal values for female goats).

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Milk production continued for approximately three years and at the end of this period, the goat and his normal, non-lactating male (fraternal) twin brother were donated for further study and euthanasia.

Serial serum sampling was conducted to form endocrine profiles of the affected goat and his twin. There was an increased serum concentrations of estradiol 17 beta, abnormal dexamethasone suppression of cortisol and an exaggerated response to ACTH in comparison with the non-lactating male. Based on these findings, a presumptive diagnosis of adrenal cortical neoplasia was made in the lactating goat.

Interestingly, ACTH did not cause increased estradiol concentrations in either the lactating male or the normal non-lactating male.

When the goat was euthanized at the end of this period, postmortem findings included nodules of adrenal hyperplasia in both adrenals, and the single large adrenal cortical adenoma in the left adrenal as shown below.

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Ether extracts of the adenoma contained more cortisol (217 versus 153 nmol/L of extract) and estradiol 17p (618 versus 189 pg/ mL of extract) than the surrounding adrenal tissue. On gross examination, the adenohypophysis was normal, and although there was  hyperplasia of acidophilic cells, the only evidence of neoplasia was in the adrenal glands.

High serum concentrations of estradiol 17 beta in the lactating male goat were probably of cardinal importance in lactogenesis. In that regard, estrogen treatment has been used to induced lactation in goats and other ruminants. Also, increased serum of estrogens are known to stimulate the release of prolactin, growth hormone (GH), IGF-1 and thyroxine; all of which were significantly elevated in this goat compared to his non-lactating brother. Finally, current literature suggests that prolactin, GH, IGF-1 and thyroxine are lactogenic and lactopoetic hormones in goats.

Lactation in male goats is not rare but it is seldom associated with neoplasia.

References  and details of the endocrinology of this case is discussed in:  Löfstedt, R.M. et al. 1994 Adrenal neoplasia causing lactation in a male goat. J Vet Internal Med. 8: 382-384