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SEER Inquiry System - Report
Produced: 10/08/2026 4:33 PM
Question 20160066
Inquiry Details
References:
#1: Subject matter expert
#2: ICD-O-3
Question:
MP/H Rules/Histology--Breast: What histology code and MP/H Rule applies to the Histologic Type of "invasive ductal carcinoma with metaplastic stroma" for a single breast tumor? See Discussion.
Discussion:
The patient had a partial mastectomy with final diagnosis of invasive ductal carcinoma with metaplastic stroma. Knowing that metaplastic breast carcinoma has a worse prognosis than other types of breast cancer, is metaplastic stroma a synonym for metaplastic carcinoma when used in this context?
Answer:
Code to metaplastic carcinoma, 8575/3. According to our expert pathologist consultant, "The term 'metaplastic stroma' implies that at least a portion of the carcinoma has undergone a 'metaplastic' change from epithelial in appearance to 'stromal' in appearance. I assume this is what CAP means by 'Invasive mammary carcinoma with matrix production,' which the WHO equates to metaplastic carcinoma."
