Mucinous (Colloid) Carcinoma

 

Epidemiology:

    • 1-6% of breast CA
    • older women

 

Common sites:

    •  

 

Gross features:

    • circumscribed mass
    • extremely soft
      • consistency and appearance of pale gray-blue gelatin

 

Histologic features:

    • clusters and small islands of cells within large lakes of mucin that push into the adjacent stroma
      • 100% of lesion
    • low-grade features (required)
    • well-circumscribed borders

 

Immunophenotype:

Marker:

Sensitivity:

Specificity:

 ER, PR

majority

 

 

Molecular features:

    • diploid
    • hypermethylation of BRCA1 promoter (55%)
    • familial:
      • slightly higher incidence in BRCA1 carriers

 

Other features:

    • slightly better prognosis than NST
    • grows slowly over many years