Treatment of Fibroadenomatous Hyperplasia in Cats with Aglépristone

Abstract

Fibroadenomatous hyperplasia (FAH) is characterized by a rapid proliferation of mammary stroma and duct epithelium of 1 or more glands and predominantly affects younger female cats. Endogenous progesterone and exogenous progestogens play an important role in the genesis of FAH. The presence of progesterone receptors in fibroadenomatous tissue allows for targeted endocrine therapy with progesterone receptor blockers. We report on 22 young cats with FAH, none of which had responded to the withdrawal of progestogens or ovariectomy. The common signs were tachycardia (11 cats); skin ulceration, painful mammary glands, or both (16 cats); lethargy (8 cats); and anorexia (4 cats). The cats were treated with subcutaneous injections of the progesterone receptor blocker aglépristone on 1 (7 cats, 20 mg/kg) or 2 consecutive days (15 cats, 10 mg/kg/d) once weekly. All but 1 cat responded with a complete and lasting remission of signs after 1-4 weeks of treatment. Two cats had a short-term skin irritation at the site of the aglépristone injection. Two pregnant cats with FAH aborted after treatment with aglépristone and subsequently developed endometritis. In conclusion, the results of this study demonstrate that FAH in cats can be treated successfully with the progesterone receptor blocker aglépristone.

What is your diagnosis?

“…It is primarily seen in young (less than two years old), sexually intact queens after progesterone treatment, at the time of puberty, or during the first oestral cycle, pregnancy or pseudopregnancy (Hayden and others 1989). In the male cat, the condition is always associated with the administration of synthetic progestagens such as megestrol acetate, delmadinon acetate or MPA (Hayden and others 1989, Görlinger and others 2002). Rarely, the condition may also be seen in older male and female cats (eight, 10 and 13 years) (Allen 1973, Hayden and others 1989, Wehrend and others 2001).…”

“…Because of the enlargement of the glands, the cats may also exhibit a reluctance to walk, discomfort and lethargy. Other less commonly reported clinical signs include tachycardia, fever, pallor of the mucous membranes and loss of appetite (Görlinger and others 2002, Loretti and others 2005).…”

“…As the condition is believed to be a hormone‐dependent lesion, mainly associated with progesterone, the anti‐progestin aglépristone has been used with high degrees of success in the treatment of feline mammary fibroepithelial hyperplasia (Wehrend and others 2001, Görlinger and others 2002, Vitasek and Dendisova 2006). When administration of antiprogestins is considered in a pregnant queen, the owner should be informed about the abortive effects of the drugs.…”

Effects of aglepristone, a progesterone receptor antagonist, in a dog with a vaginal fibroma

“…Canine benign genital tract tumours have been observed to have both oestrogen receptor‐α and progesterone receptors, just as both human and feline genital tumours do (Martín de las Mulas and others 2002, Bodner and others 2004, Millán and others 2007). Since the first description of the expression of progesterone receptors in the fibroadenomatous hyperplasia of the mammary gland of the cat (Martín de las Mulas and others 2000), the favourable response to treatment with the progesterone antagonist aglepristone has been reported by several authors (Wehrend and others 2001, Gorlinger and others 2002).…”

Histological Changes of the Feline Cervix, Endometrium and Placenta after Mid‐gestational Termination of Pregnancy with Aglepristone

“…2000), mucometra (Georgiev and Wehrend 2005) and fibroadenomatosis (Wehrend et al. 2001; Gorlinger et al. 2002; Meisl et al.…”