Apocrine adenosis of the breast: clonal evidence of neoplasia

AIMS: We report here a case of apocrine adenosis of the breast in a 66-year-old woman. To clarify the nature of this lesion, we examined it by clonal analysis. METHODS AND RESULTS: The lesion, 43 mm at its greatest dimension, was ill-circumscribed, lacking a fibrous capsule, and was composed of compact glands that showed typical histological features of apocrine adenosis. Clonality analysis, using the polymerase chain reaction (PCR)-based method for females heterozygous for a BstXI polymorphism of the X-linked phosphoglycerokinase (PGK) gene, revealed the monoclonal nature of the lesion. CONCLUSIONS: This result strongly suggests that some populations of apocrine adenosis are already neoplastic, and this could contribute to the premalignant potential of this lesion.