Pathologic Processes

 
1. Skin of the breast
 
Any disease that occurs in the integument anywhere may, and does, develop in the skin of the breast. Examples of that assertion are legion. Only a single stereotypical example of a basic pathologic process is pictured here for the purpose of illustrating our thesis.
 
a. Inflammatory

View Figure  		Fig. 1A  Psoriasis
 
b. Benign neoplastic

View Figure  		Fig. 1B  Syringoma
 
c. Malignant neoplastic

View Figure  		Fig. 1C  Melanoma
 
d. Hyperplasic

View Figure  		Fig. 1D  Verruca Vulgaris
 
e. Hamartomatous

View Figure  		Fig. 1E  Giant hairy congenital melanocytic nevus
 
f. Cyst

View Figure  		Fig. 1F  Infundibular cyst
 
g. Deposits

View Figure  		Fig. 1G  Macular amyloidosis
 
2. Subcutaneous fat of the breast
 
a. Inflammatory

View Figure  		Fig. 2A  Traumatic fat necrosis
 
b. Benign neoplastic

View Figure  		Fig. 2B  Tubular adenoma
 
c. Malignant neoplastic

View Figure  		Fig. 2C  Mucinous carcinoma
 
d. Cystic hamartomatous

View Figure  		Fig. 2D  Steatocystoma
 
3. Exceptions
 
It must be acknowledged that some pathologic processes are unique to the subcutaneous tissue of the breast, they not being found in subcutaneous tissue on any other anatomic site. Among those are the following:

View Figure  		Fig. 3A  a. Phyllodes tumor

View Figure  		Fig. 3B  b. Adenomyoepithelioma

View Figure  		Fig. 3C  c. Lobular carcinoma

View Figure  		Fig. 3D  d. Mammary Paget's disease
 
Paget's disease of the breast represents extension to the epidermis of apocrine carcinoma that begins in a lactiferous duct and ascends through that tubular epithelium to and into surface epithelium. Sebaceous carcinoma of the eyelid develops and proceeds in a manner analogous to that of mammary Paget's disease, the cells of it originating in meibonian glands and proceeding along sebaceous ducts into surface epithelium. In contrast, extramammary Paget's disease is an apocrine carcinoma that starts in the epidermis and moves down epithelial structures of adnexa, such as eccrine ducts. Although both mammary and extramammary Paget's disease are apocrine carcinomas, they are very different from one another in regard to site and prognosis, mammary Paget's disease, as a rule, being much more threatening to life.