Early Detection of Krukenberg Tumors Utilizing ctDNA Testing and CEA Monitoring.

Krukenberg tumors are rare cancers involving metastatic disease in the ovaries but classically originate from gastrointestinal malignancies, and often present diagnostic challenges due to their nonspecific symptoms and advanced stage at detection. Traditional imaging techniques like ultrasound, CT, and MRI are common methods of cancer monitoring but are limited in detecting micrometastatic disease and early-stage metastases. Circulating tumor DNA (ctDNA) testing, a noninvasive liquid biopsy method, offers a promising alternative to traditional screening methods, enabling earlier detection and precise molecular profiling of metastatic tumors. We present a case study involving a female patient who initially presented with stage IV colon cancer with oligometastatic disease to a single mesenteric lymph node. Despite neoadjuvant chemotherapy and resection of known disease, postresection ctDNA returned positive. Imaging after metastectomy failed to reveal any sites of ongoing disease, although did show a small, 2.4-cm hypodensity in the right ovary interpreted by radiology as likely an ovarian follicle. Given her ctDNA positivity, she was started on capecitabine. ctDNA levels improved, but her serum carcinoembryonic antigen (CEA) tumor marker continued to rise, and imaging subsequently revealed increased bilateral ovarian masses. She underwent bilateral salpingo-oophorectomy and total abdominal hysterectomy, with pathology confirming metastatic colon adenocarcinoma, and subsequent normalization of her CEA and ctDNA levels. Our findings underscore ctDNA's potential to complement imaging, particularly for high-risk patients, for disease monitoring and to refine therapeutic management when treating Krukenberg tumors.