Diagnostic difficulties in the differentiation between an ovarian metastatic low‑grade appendiceal mucinous neoplasm and primary ovarian mucinous cancer: A case report and literature review

Low-grade appendiceal mucinous neoplasm (LAMN) is a tumor that primarily originates from the appendix and belongs to the family of appendiceal mucinous neoplasms (AMNs). In 50% of female patients, AMNs (particularly LAMNs) have a tendency to metastasize to organs in the genital tract, where the neoplasm can mimic the features of primary ovarian mucinous cancer (POMC). The present case report reviewed the difficulties in differentiating between these two types of tumors. In the present case report, a 61-year-old female patient was admitted to the Second Department of Gynecological Surgery and Gynecological Oncology, University Clinical Hospital no. 4 at Lublin Medical University (Lublin, Poland) with the diagnosis of a right ovarian mass. After performing ultrasound and computed tomography (CT) scans and laboratory analysis, the patient underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, appendectomy and resection of the Douglas peritoneum. Notably, the postoperative pathological assessment revealed LAMN with metastases to the right ovary and omentum. Immunohistochemically, cytokeratin 20 and caudal type homeobox 2 both stained positively, whereas paired box gene 8 stained negatively. After surgery, the patient received the recommended hyperthermic intraperitoneal chemotherapy at the Department of Surgical Oncology at Lublin Medical University. After 1 year, a CT scan was performed, which indicated no evidence of recurrent disease. In conclusion, observations from the present case report suggest that gynecologists should be conscious of the possibility of malignancies of gastrointestinal origin in cases of ovarian tumors instead of making direct assumptions of POMC. If the mucinous mass involves the base of the appendix or if there is a suspicion of positive margins, then cytoreductive surgery and right-sided hemicolectomy must be performed. In addition, identifying the origin of mucinous tumors in the right ovary and/or the appendix requires the histopathological examination of a panel of markers using immunohistochemistry.