Mixed Müllerian tumor

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Mixed Müllerian tumor (ovarian carcinosarcoma) are a rare mixed mesodermal carcinosarcoma neoplasia of the canine female genital tract characterized by both carcinomatous (epithelial tissue) and sarcomatous (connective tissue) components.

Not to be confused with persistent Müllerian duct syndrome, these tumors commonly metastasize to other abdominal viscera and the lungs via hematogenous spread.

The peritoneal metastases were usually carcinomatous and pulmonary metastases sarcomatous.

Clinically affected dogs usually present with an abdominal mass, which appear as large, irregular masses associated with the ovary or uterus.

Diagnosis can be tentatively achieved based on physical appearance and locale of these tumors but definitive diagnosis requires histopathological examination of tissues obtained post-operatively.

Histologically, carcinosarcoma tumors are composed of both carcinomatous and mesenchymal components, which may be either homologous (composed of tissues normally found in the ovary) or heterologous (containing tissues which are not normally found in the ovary)[1][2].

Immunohistochemically, these tumors are usually positive for cytokeratin, vimentin and estrogen receptors, while sarcomatous cells are positive for vimentin[3].

Because of the relatively aggressive nature of these tumors, radical excision is recommended, with adjunct chemotherapy or radiation therapy if indicated on histopathological examination.

Invariably, Müllerian tumors have a poor overall survival rate.


  1. McCluggage WG (2002) Malignant biphasic uterine tumours: carcinosarcomas or metaplastic carcinomas? J Clin Pathol 55(5):321-325
  2. Brown E et al (2004) Carcinosarcoma of the ovary: 19 years of prospective data from a single center. Cancer 100(10):2148-2153
  3. Antuofermo E et al (2009) Bilateral ovarian malignant mixed Mullerian tumor in a dog. Vet Pathol 46(3):453-456