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SEER Inquiry System - Report
Produced: 06/07/2026 3:44 AM
Question 20240077
Inquiry Details
References:
2024 SEER Manual, 102-103. Example 4
Question:
2024 SEER Manual/Primary Site--Retroperitoneum: What is the primary site code for a final diagnosis of endometrioid adenocarcinoma from a biopsy of a right retroperitoneal mass? See Discussion.
Discussion:
An 80-year-old post-menopausal female (status post hysterectomy for benign reasons) presents with a retroperitoneal mass on imaging. The pre-operative imaging shows the cervix and uterus are absent. Patient undergoes a robotic left salpingo-oophorectomy with biopsy of the retroperitoneal mass.
Answer:
Code Primary Site to C480 (retroperitoneum).
Endometrial tissue may "break away” from the uterus and implant throughout the pelvic and abdominal cavities. This can occur in patients who suffer from endometriosis. This tissue remains behind when surgical removal of the uterus is done. Common sites of implantation are colon, peritoneum, retroperitoneum, and bladder. These cells may become malignant. When the uterus is no longer present (patient had surgical removal), code the site where the carcinoma was identified.
The site-morphology combination of C480 and 8380/3 was designated as an unlikely site-morphology combination by the Cancer PathCHART expert pathologist review, as this is a rare type of tumor. Assign a value of 1 in the Over-ride Site/Type [2030] data item in order to pass the Primary Site, Morphology-Type, Beh ICDO3, 2024 (SEER) edit.
