Staten Island University Hospital
Staten Island, NY
Metastasis to the colon from another primary internal malignancy is an atypical and a seldom-reported entity. The source of colorectal metastasis could be a primary neoplasm of lung, genitourinary system, breast, prostate, kidney, gastrointestinal or hepatobiliary system. The incidence of ovarian cancer metastasizing to colon is approximately 4-6%. Typically, secondary metastasis to colon from ovarian cancer occurs by peritoneal seeding and direct invasion through the colonic wall. We report a case of secondary metastasis to the colon from a primary ovarian carcinoma in the form of a mass mimicking a primary colon cancer. Interestingly, there was no disease dissemination in the pelvic cavity but solely inside the lumen of the colon, suggestive of a hematogenous or lymphatic spread rather than the typical direct invasion of metastatic ovarian cancer.
A 53-year-old female with high-grade papillary serous carcinoma of the left ovary (BRCA negative) had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy with regional lymph node resection and omentectomy. Tumor stage was T1C, N0, and AJCC stage 1C. The patient thereafter received adjuvant chemotherapy. Two years later, upon surveillance, a Positron Emission-Computed tomography (PET-CT) disclosed focal FDG uptake in the high rectum co-registering with a suspicious rectosigmoid colon wall-thickening detected on a recent contrast CT scan of abdomen and pelvis. CA 125 level was increased as well. Patient did not exhibit any rectal bleeding, abdominal pain, or weight loss. Colonoscopy showed a 5x7 cm submucosal mass at 25 cm from the anal verge, with overlying ulceration suggestive of a primary colon cancer versus a metastatic lesion Figure 1. Pathology and immunohistochemical stains unveiled the diagnosis of metastatic ovarian carcinoma Figure 2. The patient underwent robot-assisted low anterior resection of rectosigmoid. Histopathology revealed lymphovascular invasion without serosal involvement. The patient then underwent adjuvant chemotherapy with favorable results.
We believe this case was unique because of the rarity of ovarian cancer metastasizing to the colon intraluminally rather than through direct locoregional invasion. It highlights the importance of considering secondary metastasis in patients with a previous history of another primary internal malignancy. The distinction between primary colon cancer and secondary metastasis can be challenging and heightened awareness is crucial.
Figure 1: Colonoscopy picture depicting ulcerated rectosigmoid lesion
Figure 2: H&E stain (A) showing psammoma bodies, involving fragments of colonic mucosa, favoring metastatic primary ovarian cancer.
Immunohistology stain positive for CA-125 (carbohydrate antigen) (B), CK-7 (cytokeratin) (C) and negative for CK-20 (D) confirming the diagnosis of primary ovarian cancer
Anum Aqsa indicated no relevant financial relationships.
Sami Droubi indicated no relevant financial relationships.
Shivantha Amarnath indicated no relevant financial relationships.
Fady G. Haddad indicated no relevant financial relationships.
Liliane Deeb indicated no relevant financial relationships.