I am not a vet, I am a nurse & nurse-midwife.  I will speak from 'human'
breast problems.  I know NOTHING about spaying female ferrets or their
vulvas, or estrogen stimulation.  And, since ferrets & humans are BOTH
mammals, and breasts are breasts, with ducts that are meant for
lactation.  Pain in a woman's breast is more than usually benign & not
cancer.  Infection in a breast/milk duct will be painful.
 
General info on breast lumps in lactating breasts: they are most often
galactoceles or milk-filled cysts.  If it does not resolve spontaneously,
a thorough medical assessment should be made to determine the type of
blockage & possible pathology, & to rule out breast cancer.  Monitor for
any changes in the size of the breast lump.  Aspirate to determine if the
lump is fluid-filled or if it appears to be a cystic mass.  Ultrasound,
biopsy, etc.
 
Fibrocystic breasts: exaggerated response to changing hormonal
environment.  Epidemiology is poorly understood: peak incidence 30-50 yrs
(ferrets yrs?), probably related to continued estrogen stimulation (does
Luna have this????), most women (Jills?) experience fibrocystic change.
Nipple discharge may be spontaneous or provoked.  Usually white or green.
Serosanguinous must be investigated - most commonly intraductal
papilloma, breast cancer in 5% to 15%.
 
Fibroadenoma: most common benign lesion, young women, firm, painless,
mobile, multiple, bilateral in 10% to 20%, no changes in menstrual
cycle, removal usually recommended.  (THIS could be Luna.)
 
I hope this helps you in some way.  As I said I deal with HUMAN breasts.
 
Leila E Marcial, RN, CNM
mom to a soldier on the 38th parallel - Spec4 Rafael Marcial
[Posted in FML issue 4199]