Metastatic Colorectal Adenocarcinoma Involving the Endometrium Michael Deavers The University of Texas, M.D. Anderson Cancer Center Houston, TX

Clinical History The patient is a 64 year old woman who presented with vaginal bleeding. On abdominal/pelvic CT scan, there was a large area of ill defined hypodensity centered over the endometrial cavity in the mid and lower uterine body, suspicious for endometrial carcinoma. An endometrial biopsy was obtained. Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 1 - Figure 1 - Low power microphotograph of the curetting Case 1 - Figure 2 - Low power microphotograph of the curetting Case 1 - Figure 3 - Higher magnification illustrates neoplastic glands Case 1 - Figure 4 - Focal gland disorganization and desmoplasia Case 1 - Figure 5 - Cribriform arrangements with a “garland” pattern Case 1 - Figure 6 - Moderate to severe nuclear atypia Case 1 - Figure 7 - Cribriform pattern with nuclear enlargement Case 1 - Figure 8 - Luminal necrotic debris Differential Diagnosis Endometrioid Endometrial Adenocarcinoma Endocervical Adenocarcinoma Serous Carcinoma Metastatic Adenocarcinoma Discussion Points Not all adenocarcinomas identified in an EMB are from the endometrium. Cervical primaries and metastases may also be encountered in these specimens. Most patients with metastases involving the uterus have a prior history of cancer, but some metastases may mimic a primary gynecologic tumor. Approximately 1% of patients referred to a gynecologic oncologist actually have gastrointestinal primaries, and in 20-30% of those cases the metastasis is the initial presentation of their disease. While the ovary and the vagina are the most common sites of metastasis to the gynecologic tract (80% of metastases involve at least one of those two sites), the endometrium and cervix are involved in 8-9% of cases (intragenital and extragenital primaries). The ovary is the most common intragenital primary to involve the uterus. The gastrointestinal tract (stomach, colon, pancreas) and breast are the most common extragenital primaries. While it is important to consider the possibility of a metastasis in women who have a history of colorectal cancer and subsequently are found to have an adenocarcinoma involving the uterus, they are more likely to have a new endometrial primary (74%) than metastatic colonic adenocarcinoma involving the endometrium. Histologic clues for metastatic colorectal carcinoma: Tumor distinctly separate from normal endometrium. Scattered focal cytologic atypia, inappropriate for the architectural grade. Dirty necrosis. Goblet cells. Fibrotic background. Immunohistochemistry (CK7, CK20) can be useful. Final Diagnosis Metastatic Colorectal Adenocarcinoma involving the endometrium Bibliography Abu-Rustum NR, Barakat RR, Curtin JP. Ovarian and uterine disease in women with colorectal cancer. Obstet Gynecol 1997; 89:85-87. Benoit MF, Hannigan EV, Smith RP, Smith ER, Byers LJ. Primary gastrointestinal cancers presenting as gynecologic malignancies. Gynecol Oncol 2004; 95:388-392. Kumar A, Schneider V. Metastases to the uterus from extrapelvic primary tumors. Int J Gynecol Pathol 1983; 2:134-140. Kumar NB, Hart WR. Metastases to the uterine corpus from extragenital cancers. A clinicopathologic study of 63 cases. Cancer 1982; 50:2163-2169. Mazur MT, Hsueh S, Gersell DJ. Metastases to the female genital tract. Analysis of 325 cases. Cancer 1984; 53:1978-1984.