Feline Mammary Fibroadenomatous Hyperplasia: Workup

Bottom line

Mammary fibroadenomatous hyperplasia (MFH) is a benign, hormone-associated proliferation that can mimic neoplasia and develop ulceration or secondary infection. [1] Use signalment and exposure history to construct a working diagnosis, not to declare every rapidly growing mammary lesion benign. Establish which findings would require tissue confirmation or a neoplastic workup before starting a therapeutic trial.

Which history changes the diagnostic branch?

Obtain reproductive status, mating history, pregnancy possibility, prior gonadectomy records, and a complete drug history. Include injectable contraceptives and ask for the product and administration record rather than accepting “a hormone shot.”

Progestin exposure remains relevant after gonadectomy: Loretti and colleagues reported persistent hormonal influence following depot medroxyprogesterone acetate. [5] In an atypical male case without recorded progestin administration, mammary histology established MFH; the suspected exposure source was not proven. [4]

Document the chronology of enlargement and map individual glands, skin integrity, pain, and discharge. Keep photographs and measurements for subsequent comparison. Separate the working diagnosis from the immediate problem list.

Pregnancy, progesterone, and ovarian tissue

Assess pregnancy in young queens with mammary enlargement using palpation and/or abdominal ultrasonography. Investigate ovarian remnant syndrome in spayed queens with suspected hyperplasia. [2]

Serum progesterone is not a highly sensitive diagnostic indicator. Mammary ultrasound can help assess tissue and identify purulent pockets associated with mastitis. [6] Use endocrine results and imaging in context; do not equate supportive findings with histologic exclusion of malignancy.

When is tissue confirmation needed?

Histopathology confirms MFH, but incisional sampling of markedly swollen glands carries a wound-tension and healing concern. [3] Plan the sample site and closure with the pathologist and surgeon where appropriate.

If MFH cannot be established, proceed to a complete workup for a malignant process. [2] A treatment response is information to reassess, not a substitute for documenting why a mass was presumed non-neoplastic. The feline lesion-biopsy workflow offers a related framework for tying sampling to an explicit diagnostic question, although its lesion-specific differentials do not transfer to mammary tissue.

Treatment selection and reassessment

Confirmed disease can resolve after removing the progesterone source, commonly by ovariohysterectomy. [1] Published management also includes antiprogestins; pregnancy must be assessed before their use because of abortive effects. [2] This workup hub does not prescribe a dosing schedule or establish local licensing and availability.

Agree on reassessment endpoints: gland trajectory, skin viability, discomfort, discharge, food intake, and general condition. Escalate progression, new systemic illness, or a persistent discordant lesion instead of simply extending the original hypothesis. Use the feline pain and systemic triage framework when the cat is unwell.

Discuss fertility goals before selecting treatment. A report documented recurrence during subsequent gestation after successful medical management. [6] That case demonstrates possibility, not a population recurrence rate.

Frequently Asked Questions

Does rapid multigland enlargement establish MFH?

No. MFH can resemble neoplasia. [1] Keep the diagnosis provisional until the history, examination, and necessary testing are concordant.

Should pregnancy be assessed before antiprogestin treatment?

Yes. Antiprogestins can have abortive effects. [2] Establish pregnancy status and discuss reproductive goals before choosing therapy.

Does a progesterone result exclude MFH?

No. Serum progesterone is not a highly sensitive diagnostic indicator. [6] Interpret it within the reproductive and drug history.

What confirms MFH in an ambiguous case?

Mammary biopsy and histopathology are confirmatory. Marked swelling can create wound tension and impaired incision healing. [3]

Is prior spaying enough to exclude a hormonal driver?

No. Ovarian remnant syndrome warrants investigation in spayed queens with mammary hyperplasia. [2] Obtain the prior surgical history.

Can MFH occur in a male without recorded progestin therapy?

Yes. A histologically confirmed male case had no recorded progestin administration. [4] This does not establish the cause in another patient.