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Produced: 10/30/2025 9:09 PM
Question 20180071
Inquiry Details
References:
WHO Class Female Genital Tumors. 4th edition
Question:
Solid Tumor Rules (2018)/Histology--Cervix uteri: What is the correct histology code for malignant mixed Mullerian tumor (MMMT/Carcinosarcoma)? See Discussion.
Discussion:
An endometrial cancer was diagnosed in 2018. The endometrial biopsy showed malignant mixed mullerian tumor (MMMT/Carcinosarcoma). The total abdominal hysterectomy/bilateral salpingo-oophorectomy showed Endometrial Carcinosarcoma (50% serous carcinoma, 50% high grade sarcoma with rhabdomyoblastic differentiation) with invasion of 100% of the myometrium and involvement of the uterine serosa. I am not finding this in the Solid Tumor Rules or the site-specific ICD-O-3 code lists.
Answer:
According to the WHO Classificationof Tumors of Female Reproductive Organs, 4th edition, MMMT (8950/3) is now a synonym for carcinosarcoma (8980/3) even though it has a separate ICD-O code. The ICD-O code for MMMT is no longer in the WHO book. Per the subject matter experts, when both terms are used in the diagnosis (carcinosarcoma/MMMT), code the histology to 8980/3. If the ONLY term used is MMMT, assign 8950/3.
The information in the 4th edition of the WHO Classification of Tumors of Female Reproductive Organs has not yet been incorporated into the Other Sites Solid Tumor Rules.
