Abstract
Background: Apocrine gland hyperplasia (also known as apocrine nevus) is a rare condition, which can be associated with apocrine carcinoma. Apocrine carcinoma frequently harbors activating PIK3CA mutations; however, the genetic findings of apocrine gland hyperplasia and its related apocrine carcinoma are not well-known. We aimed to evaluate PIK3CA mutation status by using four cases of apocrine carcinoma arising in apocrine gland hyperplasia.
Methods: A total of four cases with apocrine carcinoma arising in apocrine gland hyperplasia were retrieved. Sanger sequencing was performed to detect PIK3CA mutations in both apocrine carcinoma and apocrine gland hyperplasia components, separately. In one case, panel sequencing was also performed for the carcinoma component.
Results: All the tumors were located in the axilla of elderly (67–85 yrs) men. In all four cases, apocrine gland hyperplasia component had no significant PIK3CA mutations. In contrast, apocrine carcinoma component harbored activating PIK3CA mutations (p.E545K, p.E726K, or p.H1047L) in all cases.
Conclusions: Apocrine gland hyperplasia does not harbor any PIK3CA mutations. Apocrine carcinoma can occur in apocrine gland hyperplasia with additional driver mutations of PIK3CA.