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Case 2 - Discussion

Surgical Pathology Case

 

ER, 20 PR, 20
 
Ki67, 20  
   
 

Mucinous Carcinoma or Colloid Carcinoma of Breast

 
  • 1% to 6% of primary breast cancers in women 75 years or older

  • Classified into pure and mixed types with areas of infiltrating ductal carcinoma

  • For pure MCB, size does not correlate with metastasis, although smaller tumors carry an excellent prognosis

  • The mucin is almost entirely extracellular

  • The incidence of axillary metastases is very low in pure MCB

  • 10-year survival rate: pure MCB, 90% to 100%;  mixed MCB, 60%

  • Differential diagnosis: 1, signet-ring carcinoma of the breast: the mucin is predominantly intracellular; 2, mucinous cystadenocarcinoma: tall columnar cells with abundant intracellular mucin

  Personal Notes
 
  • Extensive sampling is necessary to search for possible concurrent ordinary invasive carcinoma

  • Classical grading system can be used in this subtype of breast carcinoma

Reference
 
  • Annals of Surgical Oncology 9:161-164 (2002)
  • Rosai and Ackerman's Surgical Pathology, 9th edition