Ovarian mucinous adenoma with a malignant component in an adolescent: a case report

Primary ovarian mucinous adenocarcinoma in the adolescent population is extremely rare, with limited cases reported in the literature. A 14-year-old female presented with a two-week history of progressive abdominal pain, distension, bloating, early satiety, and fatigue. Physical examination revealed a significantly distended abdomen with diffuse tenderness. Contrast-enhanced CT imaging demonstrated a large multiloculated cystic adnexal mass measuring 36 × 32 × 21 cm, with displacement of bowel loops. Laboratory evaluation showed normal tumor markers except for a mildly elevated CA-125 of 47 U/mL (reference range: <35 U/mL). The patient initially underwent diagnostic laparoscopy, which was converted to open laparotomy due to the tumor’s size and complexity. Replacing the left ovary, a unilateral, encapsulated mucinous tumor was entirely excised along with the associated incorporated left ovary and fallopian tube, with preservation of the uterus and contralateral adnexa. Histopathology demonstrated mucinous cystadenoma (70%), borderline tumor (25%), and a focal invasive mucinous adenocarcinoma component (<5%), without lymphovascular or infiltrative invasion. The postoperative course was uneventful, and the patient was discharged on postoperative day 2. Upon follow up, she continued to have elevated CA-125 of 56 U/mL, and underwent staging laparoscopy, noted to be negative for any metastatic disease, repeat CA-125 normalized 13 U/mL. Long term planned follow up with routine ultrasounds and CA-125 levels. Mucinous ovarian tumors can have borderline and malignant components and therefore require a thorough histopathologic analysis.