{"paper_id":"ef04bae4-7b57-4f5e-b951-072fb28ac6ba","body_text":"Endometrial cancer is the fourth most common cancer in females, and the mortality rate has\nincreased over the past 20 years. 1  Local and distant recurrences continue to be a major concern in high-risk\npatients. 2 , 3  Well-recognized sites of\nmetastasis are the pelvic lymph nodes, paraaortic lymph nodes, vagina, peritoneum, and\nlungs, while atypical sites include the intraabdominal organs, bones, brain, abdominal wall,\nand muscle. 4  In this article, we present a rare case of metastatic endometrial cancer to the\nsigmoid colon.\n\nAn 89-year-old Caucasian female with a recent history of endometrial cancer and deep vein\nthrombosis presented to the hospital emergency department with complaint of hematochezia.\nShe underwent total laparoscopic hysterectomy and lymph node dissection 1 month prior to\nthis current presentation. The endometrial cancer was characterized as a high-grade, poorly\ndifferentiated adenocarcinoma stage 3b, strongly positive for estrogen receptor with a wild\ntype of p53. Three weeks after the surgery, she was diagnosed with proximal deep vein\nthrombosis of the right lower extremity and was started on anticoagulation with apixaban.\nWithin a week of beginning the anticoagulation, she developed bleeding per rectum. She was\nhemodynamically stable at the time of admission with a hemoglobin of 8 g/dL. The physical\nexamination was significant for right lower extremity swelling and bright red stool on\nrectal examination. Esophagogastroduodenoscopy was unremarkable; however, the colonoscopy\nrevealed severe stricture in the distal sigmoid colon ( Figure 1 ), which was subsequently biopsied. The serum\ncarcinoembryonic antigen (CEA) levels were within the normal range. Colon biopsy\ndemonstrated metastatic endometrial adenocarcinoma, with immunohistochemistry (IHC) staining\npositive for cytokeratin 7 (CK7), paired box gene 8 (Pax 8), and estrogen receptor (ER;\n Figure 2 ). The oncologist\nreferral was given to the patient for consideration of chemotherapy, but she decided to go\nwith palliative care.\nColonoscopic images demonstrating severe stricture in the distal sigmoid colon (yellow\narrow).\n(A) Cytokeratin (CK) 7 positive in endometrial tumors (arrow). (B) CK20 positive in\ncolon glands normal below (arrow), negative in tumor (arrow head). (C) Paired box gene\n(PAX) 8 positive in gynecological primaries (arrow), negative in normal colon (arrow\nhead). (D) Metastatic endometrial carcinoma.\n\nOur case exemplifies the potential for an unconventional pattern of metastasis of primary\nendometrial adenocarcinoma to the colon. Thus far, only 3 similar cases have been published\nin the literature. 2 , 3 , 5  Endometrial adenocarcinoma is the most\ncommon histologic subtype of endometrial cancer. The metastasis is mainly via lymphatic and\nhematogenous modes. 6  Hematogenous spread is commonly associated with metastasis to the lungs, brain, and bones. 7\nColon metastasis from endometrial adenocarcinoma is very rare, and it is most commonly due\nto direct spread and peritoneal seeding. The risk factors for colonic metastasis from\nendometrial adenocarcinoma include histologic grade 3, myometrial invasion >50%, age\n>60 years, lymphovascular invasion, and lower uterine involvement. 2  Endometrial and colorectal adenocarcinoma exhibit morphological similarities but have\ndifferent immunohistochemical profiles. In poorly differentiated carcinomas, IHC helps\nidentify the primary site of malignant tumors. In endometrial adenocarcinoma, IHC stains are\npositive for CK7 and ER, whereas negative for CK20. On the other hand, colonic\nadenocarcinoma IHC stains are positive for CK20 and negative for CK7 and ER. 8  Thus, the immunohistochemical phenotype pattern of CK20−/CK7+ favored the diagnosis\nof endometrial metastasis in our case.\nIn the case published by Hubers and Soni, a 75-year-old female with a remote history of\nendometrial cancer was found to have a sigmoid and proximal jejunal mass that was resected\nby exploratory laparotomy. 2  The tumors in the small bowel and sigmoid colon were histologically confirmed to be\nmetastatic endometrioid adenocarcinoma. She went into remission with chemotherapy. Molnar et\nal published a case of a 71-year-old female with a past history of endometrial\nadenocarcinoma status postsurgical resection who presented with anemia and bowel obstruction\nsymptoms 2 years after the surgery. 5  By imaging and endoscopic evaluation, she was found to have a tumor invading the left\ncolon as well as spleen and gastric antrum. She underwent left hemicolectomy, splenectomy,\nand distal gastrectomy. The histopathology confirmed the diagnosis of metastatic serous\nendometrial cancer. There have been previous reports of malignant transformation of colonic\nendometriosis into endometrial cancer, which typically arises from the serous layer of the colon. 9  In our patient, there was no history or pathological findings of endometriosis on the\nbiopsy.\n\nOur case signifies the importance of considering the colon as a metastatic site, opposed to\nan independent primary malignancy, in the setting of primary endometrial adenocarcinoma. We\ncould not ascertain the pathogenic mechanism of colonic metastasis in our case, especially\nin the absence of peritoneal carcinosis or endometriosis. Recognizing this rare but possible\npresentation will allow for appropriate diagnosis and treatment of these patients.","source_license":"CC-BY-4.0","license_restricted":false}