Mammillary fistula.

Forty women presenting with mammillary fistulas over a 6 year period have been reviewed. The events preceding the fistula were incision of a periareolar breast abscess (n = 24), breast biopsy (n = 13) and spontaneous discharge of an inflammatory mass (n = 3). Only two of the women with abscesses were lactating. Two patients had granulomatous mastitis. The remaining 36 patients were all considered to have periductal mastitis/mammary duct ectasia as the cause of their fistulas. The two mammillary fistulas associated with lactation healed spontaneously. Nine patients had the fistula excised and the wound packed; this resulted in satisfactory healing in all but one patient. Twenty-one patients had excision of the fistula and primary closure, without antibiotic cover, but only ten healed without complications and six patients required further surgical procedures for a recurrent fistula. Six patients had primary excision and closure under antibiotic cover with a penicillin and metronidazole; all healed. Mammillary fistulas are complications of the periductal mastitis/duct ectasia syndrome. They should be treated by excision and primary closure under appropriate antibiotic cover or alternatively excised and left open to granulate.