Epithelial ovarian carcinoma makes up 90-95% of all ovarian malignancies, taking into account also low-malignant-potential tumors. The Krukenberg tumor is a rare metastatic adenocarcinoma (ADK) in the ovary, representing 1-2% of ovarian tumors. Multiple primary malignant neoplasms may exist when more than one cancerous tumor is diagnosed in the same or a different organ. The incidence of multiple primary cancers among malignancies is between 2.4% to 8%. The aim of this paper is to report the case of a 47-year-old patient with two synchronous malignant tumors involving both ovaries, one diagnosed as primary papillary serous cystadenocarcinoma and the other one diagnosed as ovarian metastasis (Krukenberg tumor) of a synchronous colorectal ADK, and the complex diagnostic and therapeutic challenges that such a rare case poses. Histopathological (HP) examination and especially the immunohistochemical analysis had a determining role in differentiating between an ovarian primary tumor and a metastasis from a gastrointestinal tract cancer. The tumors examination for somatic mutations of Kirsten rat sarcoma viral oncogene homolog (KRAS) and neuroblastoma RAS viral oncogene homolog (NRAS) genes was performed in order to individualize the chemotherapic treatment in this difficult case. The conclusion of this case is that, although synchronous multiple primary cancers in a young patient are a rare condition, this situation should be taken into account in the differential diagnosis when we encounter clinical and HP diagnostic challenges.