Breast carcinoma metastasis in recurrent myxoid liposarcoma.

Tumor to tumor metastasis is a rare, but well recognized entity, most commonly involving a carcinoma metastasis to a benign or low grade mesenchymal tumor. A case of breast carcinoma metastasis in a recurrent myxoid liposarcoma is presented in this study. A 52-year-old female patient with a history of breast carcinoma (70% invasive lobular carcinoma and 30% invasive ductal carcinoma) presented with a mass in the right lumbar region. The excised mass was diagnosed as myxoid liposarcoma. The tumor recurred twice and was reexcised. Microscopic examination of the second recurrence revealed multiple foci of breast carcinoma metastases in myxoid liposarcoma. Immunohistochemical study showed staining for CK19, GCDFP-15, estrogen and progesterone in metastases. Both breast carcinoma metastasis and myxoid liposarcoma were immunoreactive for E-cadherin and beta-catenin. To our knowledge, this is the first reported case of breast carcinoma metastasis in myxoid liposarcoma, and the first occurrence of metastasis in a liposarcoma.