#1: Solid Tumor Rules (2018)
#2: Multiple primaries
#3: Corpus uteri
Source 1: 2018 Solid Tumor Rules
Notes: Other Sites, Updated 9/11/2018
Solid Tumor Rules (2018)/Multiple primaries--Corpus uteri: How many primaries are accessioned for patient with a minimally invasive endometrial adenocarcinoma arising in a polyp in 2001, followed by a metastatic poorly differentiated clear cell carcinoma of gynecologic (GYN) origin in 2019? See Discussion.
The patient has a history of a minimally invasive endometrial adenocarcinoma that was low grade and confined to an endometrial polyp in 2001. The patient underwent a total abdominal hysterectomy/bilateral salpingo-oophorectomy (TAH/BSO) that entirely removed the tumor at that time.
Almost 18 years later, the patient had a left inguinal mass excision that was, Carcinoma of gynecologic origin, consistent with clear cell carcinoma. No other disease was found, the physician never indicated whether this was felt to be metastatic from the previous, low grade adenocarcinoma or not. It was only noted as, an unusual malignancy of the left lower quadrant and inguinal region of gynecologic origin. No further information was available in the medical record or from the physician on follow-up.
Although neither the Solid Tumor Rules nor the MPH Rules (still in use for the Other Sites schema) apply to metastasis, given the differences in histology and behavior of these two tumors (i.e., minimally invasive, low grade disease diagnosed in 2001 vs. higher grade, more aggressive tumor in 2019) should the current clear cell carcinoma of GYN origin really be considered the same primary as the 2001 endometrial adenocarcinoma?
Abstract a multiple primaries using 2018 Other Sites Solid Tumor Rule M10 as these tumors are more than one year apart. This represents endometrioid adenocarcinoma (8380/3 of C541) and 18 years later, clear cell Carcinoma (8310/3 consistent with GYN (C579) primary).