90% of cases are smokers, however only a very small fraction of smokers appear to develop this lesion. It has been speculated that either the direct toxic effect or hormonal changes related to smoking could cause squamous metaplasia of lactiferous ducts. It is not well established whether the lesion regresses after smoking cessation. Extrapuerperal cases are often associated with hyperprolactinemia or with thyroid problems. Also diabetes mellitus may be a contributing factor in nonpuerperal breast<unk> .
Subareolar abscess
Ciliated cyst of the vulva
Periapical cyst
Limbal nodule
Cutaneous endometriosis
Giant condyloma acuminatum
Multiple cutaneous leiomyoma
Trichilemmoma