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Background
Tumours that metastasize to the ovary can occur in conjunction with other ovarian lesions, including benign sex cord stroma tumours like fibroma or fibrothecoma. This case report presents a unique instance of metastatic signet ring carcinoma involving the ovary in a background of fibroma in a Black African woman.
Patient presentation
A 46-year-old gravida 3, para 0 (2 alive), patient was referred from the general outpatient clinic to the gynecology clinic due to progressive abdominal swelling over the past eight months. Abdominal examination revealed marked distension with massive ascites. Physical examination of the chest demonstrated dullness to percussion over both lung bases, with increased dullness noted on the right. Auscultation revealed decreased air entry in the right middle and lower lung zones, with normal to increased air entry in the remaining lung fields. Abdominopelvic ultrasound revealed a large irregularly marginated homogeneous solid mass in the right adnexa measuring 16.4 × 11.7 × 12.7 cm. An abdominal CT scan revealed bilateral pleural effusion, which was more pronounced on the right, ascites, and evidence of pulmonary and hepatic metastasis. Serum chemistry revealed abnormal levels of several analytes, including elevated CA 125 at 1,108.8 (normal range 0–35) U/L and CA 19–9 at 63.8 (normal range 0–35) U/L. She subsequently underwent staging laparotomy with total abdominal hysterectomy and bilateral salpingo-oophorectomy, without any postoperative complications. The histologic sections of the right and left ovaries revealed a moderately cellular lesion composed of intersecting bundles of spindle cells in a fascicular and storiform pattern. Additionally, pockets of small round to oval-shaped cells with intracytoplasmic clear vacuoles pushing the nucleus to the periphery (signet ring cells) were identified in a few foci. These cells were initially thought to be ovarian stroma or theca cells. Microscopic examination revealed signet ring cells with cytoplasmic positivity for periodic acid-Schiff (PAS) staining. The histopathological diagnosis was metastatic signet ring cell carcinoma involving the ovary, with an underlying ovarian fibroma.
Conclusions
Ovarian metastatic signet ring carcinoma in a background of fibroma can pose a significant diagnostic challenge, as signet ring cells can mimic the ovarian stroma or theca cells, especially if they are only observed in a few foci of the sections.