6. Extragenital primary malignant mixed mullerian tumour - A case presentation

Abstract

<h3>Background</h3> Malignant mixed mullerian tumour (MMMT) is an uncommon, often aggressive malignancy of the female reproductive system, typically arising from the uterus. Histologically, this neoplasm exhibits a biphasic tissue pattern with sarcomatous and carcinomatous elements. Whilst this tumour is known to metastasise outside of the reproductive tract, case reports of its occurrence as an extragenital primary malignancy are exceedingly rare. <h3>Case</h3> The following case was seen in 2013 at the Gold Coast Hospital, Queensland. A 67-year-old woman presented to the surgical outpatient clinic complaining of several months of increasing abdominal discomfort. She reported a past history of ER/PR negative breast cancer, which was treated with surgery (unilateral mastectomy) and chemotherapy. She had also undergone a total hysterectomy and bilateral salpingo-oophorectomy many years earlier for abnormal per-vaginal bleeding. After further investigation, she was found to have a large intraabdominal mass within her right iliac fossa, adhered to the anterior abdominal wall. The 23 × 19 cm mass was surgically removed. Macroscopic examination revealed a blood-filled cystic lesion with a thickened wall and necrotic internal lining. Microscopic examination showed predominantly sarcomatous tissue composed of spindle cells, with interspersed nests and trabeculae of malignant epithelial cells, together suggestive of carcinosarcoma. Further immunohistochemical staining confirmed this diagnosis. <h3>Discussion</h3> Given this woman's history of a hysterectomy and bilateral salpingo-oophorectomy more than 30 years prior to this presentation, the favoured diagnosis was an extragenital primary MMMT (as opposed to metastatic disease), potentially arising from pre-existing endometriosis, or from mullerian remnants. There are very few case reports of this particular diagnosis, and as such the subsequent paucity of effective treatment options means this malignancy continues to carry an overall poor prognosis.