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Looking at treatment of feline mammary fibroepithelial hyperplasia

de Melo EH, Câmara DR, Notomi MK, Jabour FF, Garrido RA, Nogueira AC, et al. Effectiveness of ovariohysterectomy on feline mammary fibroepithelial hyperplasia treatment. J Feline Med Surg [Internet]. 2020 Aug 19 [cited 2020 Aug 24].

Feline mammary fibroepithelial hyperplasia (FMFH; also mammary gland hyperplasia, mammary hypertrophy) characterized by the fairly rapid development of non-neoplastic mammary tissue. Multiple glands are usually affected, and tissue is firm and may be ulcerated, bleeding or necrotic. This condition occurs as a result of exposure to progestins, which may be endogenous or exogenous. Exogenous progestin exposure is less common in recent times as the use of synthetic progestins in feline medicine has become less common. Endogenous progestins are most often secreted from the ovaries of intact female cats. Treatment of this condition may be medical (though the use of antiprogesterone drugs such as aglepristone), through mastectomy, or ovario- or ovariohysterectomy. Medical therapy alone may take many weeks and disease can recur after therapy stops. Mastectomy is often avoided, as the large and atypical tissue makes surgery difficult.

The purpose of this study was to determine the effectiveness of ovariohysterectomy (OVH) alone or in combination with antiprogestins to treat FMFH. The study was designed as a retrospective observational study of 79 cats treated by a non-profit pet population control organization.

Cats were diagnosed with FMFH based on a combination of clinical signs and cytology. Cats with open wounds were managed with amoxicillin-clavulanate potassium, ketoprofen, topical chlorhexidine, and bacitracin-neomycin ointment. OVH was generally performed with a ventral midline approach, but a flank approach was taken in cases with excessive mammary growth. Ketoprofen and antibiotics were continued post surgically for 4 days. After OVH, cats were examined every 7-10 days for evidence of remission of FMFH. If disease continued for 3-weeks they were administered an injectable antiprogestin. Data on signalment, prior exogenous progestin use, response to therapy, and treatments were recorded.

Of the 79 cats included in the study, 63.3% had received prior exogenous progestin therapy. The interval between progestin therapy and first signs of FMFH ranged from 7-30 days.

After OVH, persistent mammary growth was noted in 24% of cats, 94.7% of which were previously exposed to exogenous progestins.

Six cats (7.6%), all of which were treated with progestins, died over the course of the study. These cats all had persistent mammary growth noted after OVH. The remaining 73 cats all attained full remission. OVH alone was successful in 94.4% of cats, while antiprogestin therapy was utilized in 5.6%. The cats that required antiprogestin therapy had all received exogenous progestins previously.

Overall, the use of synthetic progestins was associated with a higher risk of persistent mammary growth, a longer interval between OVH and remission, and a non-significant trend towards higher mortality.

There are several limitations of this study. The retrospective nature may introduce some bias. There was no effort to placebo control or blind investigators. The only progestin investigated by the authors was medroxyprogesterone acetate (administered for estrus suppression); other progestins may have different effects.

The authors conclude that in cats with spontaneous FMFH, OVH is a safe and effective option. In cats with FMHV, OHV is a reasonable step, but there is a higher risk they will require antiprogestin therapy. Cats developing FMHV after synthetic progestin therapy may also have a higher risk of death. Mastectomy is not a necessary step in the treatment of this condition. (MRK)

See also:

Jurka P, Max A. Treatment of fibroadenomatosis in 14 cats with aglepristone – changes in blood parameters and follow-up. Vet Rec 2009; 165: 657–660.

Loretti AP, Ilha MRS, Ordás J, et al. Clinical, pathological and immunohistochemical study of feline mammary fibroepithelial hyperplasia following a single injection of depot medroxyprogesterone acetate. J Feline Med Surg 2005; 7: 43–52.