RESIDENT CASE STUDIES

Week 8 June 9 - June 13, 2003: Case 3   

Table of Contents | List of Diagnoses | Case 1 | Case 2 | Case 3

18 year old female with right breast mass

Discussion 
Adenosis tumor of the breast is a benign proliferative breast disease, the main feature of which is the proliferation of the glandular component of the breast. The whole breast lesion/mass is replaced by this glandular proliferation with little or no stromal component. The lobular architecture of the breast, though expanded is preserved. 

Other benign proliferative breast diseases include fibroadenoma, papilloma, adenosis, epitheliosis. Other frequent adenoses occurring in practice are: blunt duct adenosis, sclerosing adenosis, nodular adenosis, and florid adenosis. The less frequent adenoses are: microglandular adenosis, tubular adenosis, apocrine adenosis, and myoepithelial (adenomyoepithelial) adenosis. Blunt duct adenosis may be associated with a family history of breast cancer.¹ 

Adenosis may be mistaken for fibroadenoma, (especially juvenile fibroadenoma) or tubular carcinoma. Fibroadenoma usually has proliferation of the glandular and stromal components, while adenosis is predominantly proliferation of the glandular components. Myoepithelial cell layer, though present, may not be seen in all the glands. This may lead to thinking of tubular carcinoma. Low power examination showing the lobular architecture without any infiltrating pattern will usually help rule out carcinoma. This emphasizes the wisdom of low power examination of  breast tissue. 

References:

¹Cook MG, Rohan TE. Benign breast disease: the relationship between its histological features and risk factors for breast cancer. Pathology. 1991 Oct;23(4):286-90.